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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "content/public/common/content_switches.h"
      6 
      7 #include "base/command_line.h"
      8 
      9 namespace switches {
     10 
     11 // The number of MSAA samples for canvas2D. Requires MSAA support by GPU to
     12 // have an effect. 0 disables MSAA.
     13 const char kAcceleratedCanvas2dMSAASampleCount[] = "canvas-msaa-sample-count";
     14 
     15 // By default, file:// URIs cannot read other file:// URIs. This is an
     16 // override for developers who need the old behavior for testing.
     17 const char kAllowFileAccessFromFiles[]      = "allow-file-access-from-files";
     18 
     19 // Allows frames with an https origin to use WebSockets with an insecure URL
     20 // (ws://).
     21 const char kAllowInsecureWebSocketFromHttpsOrigin[] =
     22     "allow-insecure-websocket-from-https-origin";
     23 
     24 // Allows loopback interface to be added in network list for peer connection.
     25 const char kAllowLoopbackInPeerConnection[] =
     26     "allow-loopback-in-peer-connection";
     27 
     28 // Enables the sandboxed processes to run without a job object assigned to them.
     29 // This flag is required to allow Chrome to run in RemoteApps or Citrix. This
     30 // flag can reduce the security of the sandboxed processes and allow them to do
     31 // certain API calls like shut down Windows or access the clipboard. Also we
     32 // lose the chance to kill some processes until the outer job that owns them
     33 // finishes.
     34 const char kAllowNoSandboxJob[]             = "allow-no-sandbox-job";
     35 
     36 // Allows debugging of sandboxed processes (see zygote_main_linux.cc).
     37 const char kAllowSandboxDebugging[]         = "allow-sandbox-debugging";
     38 
     39 // The same as kAuditHandles except all handles are enumerated.
     40 const char kAuditAllHandles[]               = "enable-handle-auditing-all";
     41 
     42 // Enumerates and prints a child process' most dangerous handles when it
     43 // is terminated.
     44 const char kAuditHandles[]                  = "enable-handle-auditing";
     45 
     46 // Choose which logging channels in blink platform to activate.  See
     47 // Logging.cpp in blink's Source/platform for a list of available channels.
     48 const char kBlinkPlatformLogChannels[]      = "blink-platform-log-channels";
     49 
     50 // Block cross-site documents (i.e., HTML/XML/JSON) from being loaded in
     51 // subresources when a document is not supposed to read them.  This will later
     52 // allow us to block them from the entire renderer process when site isolation
     53 // is enabled.
     54 const char kBlockCrossSiteDocuments[]     = "block-cross-site-documents";
     55 
     56 // Causes the browser process to throw an assertion on startup.
     57 const char kBrowserAssertTest[]             = "assert-test";
     58 
     59 // Causes the browser process to crash on startup.
     60 const char kBrowserCrashTest[]              = "crash-test";
     61 
     62 // Path to the exe to run for the renderer and plugin subprocesses.
     63 const char kBrowserSubprocessPath[]         = "browser-subprocess-path";
     64 
     65 // Dumps extra logging about plugin loading to the log file.
     66 const char kDebugPluginLoading[] = "debug-plugin-loading";
     67 
     68 // Sets the tile size used by composited layers.
     69 const char kDefaultTileWidth[]              = "default-tile-width";
     70 const char kDefaultTileHeight[]             = "default-tile-height";
     71 
     72 // Disable antialiasing on 2d canvas.
     73 const char kDisable2dCanvasAntialiasing[]   = "disable-canvas-aa";
     74 
     75 // Disables client-visible 3D APIs, in particular WebGL and Pepper 3D.
     76 // This is controlled by policy and is kept separate from the other
     77 // enable/disable switches to avoid accidentally regressing the policy
     78 // support for controlling access to these APIs.
     79 const char kDisable3DAPIs[]                 = "disable-3d-apis";
     80 
     81 // Disable gpu-accelerated 2d canvas.
     82 const char kDisableAccelerated2dCanvas[]    = "disable-accelerated-2d-canvas";
     83 
     84 // Disables layer squashing.
     85 const char kDisableLayerSquashing[] =
     86     "disable-layer-squashing";
     87 
     88 // Disables hardware acceleration of video decode, where available.
     89 const char kDisableAcceleratedVideoDecode[] =
     90     "disable-accelerated-video-decode";
     91 
     92 // Disable the ApplicationCache.
     93 const char kDisableApplicationCache[]       = "disable-application-cache";
     94 
     95 // Disable limits on the number of backing stores. Can prevent blinking for
     96 // users with many windows/tabs and lots of memory.
     97 const char kDisableBackingStoreLimit[]      = "disable-backing-store-limit";
     98 
     99 // Disable the creation of compositing layers when it would prevent LCD text.
    100 const char kDisablePreferCompositingToLCDText[] =
    101     "disable-prefer-compositing-to-lcd-text";
    102 
    103 // See comment for kEnableCompositingForTransition.
    104 const char kDisableCompositingForTransition[] =
    105      "disable-transition-compositing";
    106 
    107 // Disables HTML5 DB support.
    108 const char kDisableDatabases[]              = "disable-databases";
    109 
    110 // Disables delegated renderer.
    111 const char kDisableDelegatedRenderer[]      = "disable-delegated-renderer";
    112 
    113 // Disables desktop notifications (default enabled on windows).
    114 const char kDisableDesktopNotifications[]   = "disable-desktop-notifications";
    115 
    116 // Handles URL requests by NPAPI plugins through the renderer.
    117 const char kDisableDirectNPAPIRequests[]    = "disable-direct-npapi-requests";
    118 
    119 // Disable the per-domain blocking for 3D APIs after GPU reset.
    120 // This switch is intended only for tests.
    121 extern const char kDisableDomainBlockingFor3DAPIs[] =
    122     "disable-domain-blocking-for-3d-apis";
    123 
    124 // Disable experimental WebGL support.
    125 const char kDisableExperimentalWebGL[]      = "disable-webgl";
    126 
    127 // Disable FileSystem API.
    128 const char kDisableFileSystem[]             = "disable-file-system";
    129 
    130 // Disable 3D inside of flapper.
    131 const char kDisableFlash3d[]                = "disable-flash-3d";
    132 
    133 // Disable Stage3D inside of flapper.
    134 const char kDisableFlashStage3d[]           = "disable-flash-stage3d";
    135 
    136 // Disables GPU hardware acceleration.  If software renderer is not in place,
    137 // then the GPU process won't launch.
    138 const char kDisableGpu[]                    = "disable-gpu";
    139 
    140 // Prevent the compositor from using its GPU implementation.
    141 const char kDisableGpuCompositing[]         = "disable-gpu-compositing";
    142 
    143 // Disable the limit on the number of times the GPU process may be restarted
    144 // This switch is intended only for tests.
    145 extern const char kDisableGpuProcessCrashLimit[] =
    146     "disable-gpu-process-crash-limit";
    147 
    148 // Disable GPU rasterization, i.e. rasterize on the CPU only.
    149 // Overrides the kEnableGpuRasterization and kForceGpuRasterization flags.
    150 const char kDisableGpuRasterization[]       = "disable-gpu-rasterization";
    151 
    152 // When using CPU rasterizing disable low resolution tiling. This uses
    153 // less power, particularly during animations, but more white may be seen
    154 // during fast scrolling especially on slower devices.
    155 const char kDisableLowResTiling[] = "disable-low-res-tiling";
    156 
    157 // Disable the GPU process sandbox.
    158 const char kDisableGpuSandbox[]             = "disable-gpu-sandbox";
    159 
    160 // Disable the thread that crashes the GPU process if it stops responding to
    161 // messages.
    162 const char kDisableGpuWatchdog[]            = "disable-gpu-watchdog";
    163 
    164 // Suppresses hang monitor dialogs in renderer processes.  This may allow slow
    165 // unload handlers on a page to prevent the tab from closing, but the Task
    166 // Manager can be used to terminate the offending process in this case.
    167 const char kDisableHangMonitor[]            = "disable-hang-monitor";
    168 
    169 // Disable the RenderThread's HistogramCustomizer.
    170 const char kDisableHistogramCustomizer[]    = "disable-histogram-customizer";
    171 
    172 // Paint content on the main thread instead of the compositor thread.
    173 // Overrides the kEnableImplSidePainting flag.
    174 const char kDisableImplSidePainting[]       = "disable-impl-side-painting";
    175 
    176 // Prevent Java from running.
    177 const char kDisableJava[]                   = "disable-java";
    178 
    179 // Don't execute JavaScript (browser JS like the new tab page still runs).
    180 const char kDisableJavaScript[]             = "disable-javascript";
    181 
    182 // Don't kill a child process when it sends a bad IPC message.  Apart
    183 // from testing, it is a bad idea from a security perspective to enable
    184 // this switch.
    185 const char kDisableKillAfterBadIPC[]        = "disable-kill-after-bad-ipc";
    186 
    187 // Disables prefixed Encrypted Media API (e.g. webkitGenerateKeyRequest()).
    188 const char kDisablePrefixedEncryptedMedia[] =
    189     "disable-prefixed-encrypted-media";
    190 
    191 // Disables LCD text.
    192 const char kDisableLCDText[]                = "disable-lcd-text";
    193 
    194 // Disables distance field text.
    195 const char kDisableDistanceFieldText[]      = "disable-distance-field-text";
    196 
    197 // Disable LocalStorage.
    198 const char kDisableLocalStorage[]           = "disable-local-storage";
    199 
    200 // Force logging to be disabled.  Logging is enabled by default in debug
    201 // builds.
    202 const char kDisableLogging[]                = "disable-logging";
    203 
    204 // Disables Media Source API (i.e., the MediaSource object).
    205 const char kDisableMediaSource[]            = "disable-media-source";
    206 
    207 // Disable Pepper3D.
    208 const char kDisablePepper3d[]               = "disable-pepper-3d";
    209 
    210 // Disables compositor-accelerated touch-screen pinch gestures.
    211 const char kDisablePinch[]                  = "disable-pinch";
    212 
    213 // Prevent plugins from running.
    214 const char kDisablePlugins[]                = "disable-plugins";
    215 
    216 // Disable discovering third-party plug-ins. Effectively loading only
    217 // ones shipped with the browser plus third-party ones as specified by
    218 // --extra-plugin-dir and --load-plugin switches.
    219 const char kDisablePluginsDiscovery[]       = "disable-plugins-discovery";
    220 
    221 // Disables remote web font support. SVG font should always work whether this
    222 // option is specified or not.
    223 const char kDisableRemoteFonts[]            = "disable-remote-fonts";
    224 
    225 // Turns off the accessibility in the renderer.
    226 const char kDisableRendererAccessibility[]  = "disable-renderer-accessibility";
    227 
    228 // Disable the seccomp filter sandbox (seccomp-bpf) (Linux only).
    229 const char kDisableSeccompFilterSandbox[]   = "disable-seccomp-filter-sandbox";
    230 
    231 // Disable session storage.
    232 const char kDisableSessionStorage[]         = "disable-session-storage";
    233 
    234 // Disable the setuid sandbox (Linux only).
    235 const char kDisableSetuidSandbox[]          = "disable-setuid-sandbox";
    236 
    237 // Disable shared workers.
    238 const char kDisableSharedWorkers[]          = "disable-shared-workers";
    239 
    240 // For tests, disable single thread scheduler and only manually composite.
    241 const char kDisableSingleThreadProxyScheduler[] =
    242     "disable-single-thread-proxy-scheduler";
    243 
    244 // Disable smooth scrolling for testing.
    245 const char kDisableSmoothScrolling[]        = "disable-smooth-scrolling";
    246 
    247 // Disables the use of a 3D software rasterizer.
    248 const char kDisableSoftwareRasterizer[]     = "disable-software-rasterizer";
    249 
    250 // Disable multithreaded GPU compositing of web content.
    251 const char kDisableThreadedCompositing[]     = "disable-threaded-compositing";
    252 
    253 // Disable multithreaded, compositor scrolling of web content.
    254 const char kDisableThreadedScrolling[]      = "disable-threaded-scrolling";
    255 
    256 // Disable V8 idle notification after commit.
    257 // Overrides kEnableV8IdleNotificationAfterCommit.
    258 const char kDisableV8IdleNotificationAfterCommit[] =
    259     "disable-v8-idle-notification-after-commit";
    260 
    261 // Don't enforce the same-origin policy. (Used by people testing their sites.)
    262 const char kDisableWebSecurity[]            = "disable-web-security";
    263 
    264 // Disables support for XSLT.
    265 const char kDisableXSLT[]                   = "disable-xslt";
    266 
    267 // Disables Blink's XSSAuditor. The XSSAuditor mitigates reflective XSS.
    268 const char kDisableXSSAuditor[]             = "disable-xss-auditor";
    269 
    270 // Disable rasterizer that writes directly to GPU memory associated with tiles.
    271 // Overrides the kEnableZeroCopy flag.
    272 const char kDisableZeroCopy[]               = "disable-zero-copy";
    273 
    274 // Specifies if the |DOMAutomationController| needs to be bound in the
    275 // renderer. This binding happens on per-frame basis and hence can potentially
    276 // be a performance bottleneck. One should only enable it when automating dom
    277 // based tests.
    278 const char kDomAutomationController[]       = "dom-automation";
    279 
    280 // Enable partially decoding jpeg images using the GPU.
    281 // At least YUV decoding will be accelerated when using this flag.
    282 // Has no effect unless GPU rasterization is enabled.
    283 const char kEnableAcceleratedJpegDecoding[] =
    284     "enable-accelerated-jpeg-decoding";
    285 
    286 // Enable bleeding-edge code to make Chrome draw content faster. The changes
    287 // behind this path are very likely to break lots of content.
    288 // ** DO NOT use this flag unless you know what you are doing. **
    289 const char kEnableBleedingEdgeRenderingFastPaths[] =
    290     "enable-bleeding-edge-rendering-fast-paths";
    291 
    292 // Disable deferred image filters.
    293 const char kDisableDeferredFilters[]         = "disable-deferred-filters";
    294 
    295 // Enables LCD text.
    296 const char kEnableLCDText[]                 = "enable-lcd-text";
    297 
    298 // Enables using signed distance fields when rendering text.
    299 // Only valid if GPU rasterization is enabled as well.
    300 const char kEnableDistanceFieldText[]       = "enable-distance-field-text";
    301 
    302 // Enables experimental feature that maps multiple RenderLayers to
    303 // one composited layer to avoid pathological layer counts.
    304 const char kEnableLayerSquashing[] =
    305     "enable-layer-squashing";
    306 
    307 // Enable experimental container node culling.
    308 const char kEnableContainerCulling[]        = "enable-container-culling";
    309 
    310 // Use a BeginFrame signal from browser to renderer to schedule rendering.
    311 const char kEnableBeginFrameScheduling[]    = "enable-begin-frame-scheduling";
    312 
    313 // Enable the creation of compositing layers when it would prevent LCD text.
    314 const char kEnablePreferCompositingToLCDText[] =
    315     "enable-prefer-compositing-to-lcd-text";
    316 
    317 // PlzNavigate: Use the experimental browser-side navigation path.
    318 const char kEnableBrowserSideNavigation[]   = "enable-browser-side-navigation";
    319 
    320 // Enable/Disable the creation of compositing layers for RenderLayers with a
    321 // transition on a property that supports accelerated animation (that is,
    322 // opacity, -webkit-transform, and -webkit-filter), even when no animation is
    323 // running. These options allow for three possible scenarios:
    324 //  1. Default (enabled only if we dectect a highDPI display)
    325 //  2. Enabled always.
    326 //  3. Disabled always.
    327 const char kEnableCompositingForTransition[] =
    328      "enable-transition-compositing";
    329 
    330 // Defer image decoding in WebKit until painting.
    331 const char kEnableDeferredImageDecoding[]   = "enable-deferred-image-decoding";
    332 
    333 // Enables delegated renderer.
    334 const char kEnableDelegatedRenderer[]       = "enable-delegated-renderer";
    335 
    336 // Enables display list based 2d canvas implementation.
    337 const char kEnableDisplayList2dCanvas[]     = "enable-display-list-2d-canvas";
    338 const char kDisableDisplayList2dCanvas[]     = "disable-display-list-2d-canvas";
    339 
    340 // Enables restarting interrupted downloads.
    341 const char kEnableDownloadResumption[]      = "enable-download-resumption";
    342 
    343 // Enables support for Encrypted Media Extensions (e.g. MediaKeys).
    344 const char kEnableEncryptedMedia[] = "enable-encrypted-media";
    345 
    346 // Enable experimental canvas features, e.g. canvas 2D context attributes
    347 const char kEnableExperimentalCanvasFeatures[] =
    348     "enable-experimental-canvas-features";
    349 
    350 // Enables Web Platform features that are in development.
    351 const char kEnableExperimentalWebPlatformFeatures[] =
    352     "enable-experimental-web-platform-features";
    353 
    354 // By default, cookies are not allowed on file://. They are needed for testing,
    355 // for example page cycler and layout tests. See bug 1157243.
    356 const char kEnableFileCookies[]             = "enable-file-cookies";
    357 
    358 // Enables TRACE for GL calls in the renderer.
    359 const char kEnableGpuClientTracing[]        = "enable-gpu-client-tracing";
    360 
    361 // Allow heuristics to determine when a layer tile should be drawn with the
    362 // Skia GPU backend. Only valid with GPU accelerated compositing +
    363 // impl-side painting.
    364 const char kEnableGpuRasterization[]        = "enable-gpu-rasterization";
    365 
    366 // When using CPU rasterizing generate low resolution tiling. Low res
    367 // tiles may be displayed during fast scrolls especially on slower devices.
    368 const char kEnableLowResTiling[] = "enable-low-res-tiling";
    369 
    370 // Paint content on the compositor thread instead of the main thread.
    371 const char kEnableImplSidePainting[]        = "enable-impl-side-painting";
    372 
    373 // Force logging to be enabled.  Logging is disabled by default in release
    374 // builds.
    375 const char kEnableLogging[]                 = "enable-logging";
    376 
    377 // Enables the memory benchmarking extension
    378 const char kEnableMemoryBenchmarking[]      = "enable-memory-benchmarking";
    379 
    380 // Enables the network information API.
    381 const char kEnableNetworkInformation[]      = "enable-network-information";
    382 
    383 // Enable rasterizer that writes directly to GPU memory.
    384 const char kEnableOneCopy[]                 = "enable-one-copy";
    385 
    386 // Enables use of hardware overlay for fullscreen video playback. Android only.
    387 const char kEnableOverlayFullscreenVideo[]  = "enable-overlay-fullscreen-video";
    388 
    389 // Forward overscroll event data from the renderer to the browser.
    390 const char kEnableOverscrollNotifications[] = "enable-overscroll-notifications";
    391 
    392 // Enables compositor-accelerated touch-screen pinch gestures.
    393 const char kEnablePinch[]                   = "enable-pinch";
    394 
    395 // Make the values returned to window.performance.memory more granular and more
    396 // up to date in shared worker. Without this flag, the memory information is
    397 // still available, but it is bucketized and updated less frequently. This flag
    398 // also applys to workers.
    399 const char kEnablePreciseMemoryInfo[] = "enable-precise-memory-info";
    400 
    401 // Set options to cache V8 data. (off, preparse data, or code)
    402 const char kV8CacheOptions[] = "v8-cache-options";
    403 
    404 // Enables the CSS multicol implementation that uses the regions implementation.
    405 const char kEnableRegionBasedColumns[] =
    406     "enable-region-based-columns";
    407 
    408 // Replaces renderer-browser IPC channel with ChnanelMojo.
    409 const char kEnableRendererMojoChannel[] =
    410     "enable-renderer-mojo-channel";
    411 
    412 // Cause the OS X sandbox write to syslog every time an access to a resource
    413 // is denied by the sandbox.
    414 const char kEnableSandboxLogging[]          = "enable-sandbox-logging";
    415 
    416 // Enables seccomp-bpf support for Android. Requires experimental kernel
    417 // support. <http://crbug.com/166704>
    418 const char kEnableSeccompFilterSandbox[] =
    419     "enable-seccomp-filter-sandbox";
    420 
    421 // Enables the Skia benchmarking extension
    422 const char kEnableSkiaBenchmarking[]        = "enable-skia-benchmarking";
    423 
    424 // On platforms that support it, enables smooth scroll animation.
    425 const char kEnableSmoothScrolling[]         = "enable-smooth-scrolling";
    426 
    427 // Enable spatial navigation
    428 const char kEnableSpatialNavigation[]       = "enable-spatial-navigation";
    429 
    430 // Enables StatsTable, logging statistics to a global named shared memory table.
    431 const char kEnableStatsTable[]              = "enable-stats-table";
    432 
    433 // Experimentally ensures that each renderer process:
    434 // 1) Only handles rendering for pages from a single site, apart from iframes.
    435 // (Note that a page can reference content from multiple origins due to images,
    436 // JavaScript files, etc.  Cross-site iframes are also loaded in-process.)
    437 // 2) Only has authority to see or use cookies for the page's top-level origin.
    438 // (So if a.com iframes b.com, the b.com network request will be sent without
    439 // cookies.)
    440 // This is expected to break compatibility with many pages for now.  Unlike the
    441 // --site-per-process flag, this allows cross-site iframes, but it blocks all
    442 // cookies on cross-site requests.
    443 const char kEnableStrictSiteIsolation[]     = "enable-strict-site-isolation";
    444 
    445 // Enable support for sync events in ServiceWorkers.
    446 const char kEnableServiceWorkerSync[]       = "enable-service-worker-sync";
    447 
    448 // Enable use of experimental TCP sockets API for sending data in the
    449 // SYN packet.
    450 const char kEnableTcpFastOpen[]             = "enable-tcp-fastopen";
    451 
    452 // Enabled threaded compositing for layout tests.
    453 const char kEnableThreadedCompositing[]     = "enable-threaded-compositing";
    454 
    455 // Enable tracing during the execution of browser tests.
    456 const char kEnableTracing[]                 = "enable-tracing";
    457 
    458 // The filename to write the output of the test tracing to.
    459 const char kEnableTracingOutput[]           = "enable-tracing-output";
    460 
    461 // Enable screen capturing support for MediaStream API.
    462 const char kEnableUserMediaScreenCapturing[] =
    463     "enable-usermedia-screen-capturing";
    464 
    465 // Enables streaming scripts to V8 while loading.
    466 const char kEnableV8ScriptStreaming[] = "enable-v8-script-streaming";
    467 
    468 // Send a notification from RenderWidgetCompositor to V8 to do idle work
    469 // (e.g. garbage collection) after the commit until the beginning of the next
    470 // frame.  This moves the work off the critical path where compositor is waiting
    471 // for the main thread. The flag is experimental until the implementation of the
    472 // V8 idle handler is completed.
    473 const char kEnableV8IdleNotificationAfterCommit[] =
    474     "enable-v8-idle-notification-after-commit";
    475 
    476 // Enables the use of the @viewport CSS rule, which allows
    477 // pages to control aspects of their own layout. This also turns on touch-screen
    478 // pinch gestures.
    479 const char kEnableViewport[]                = "enable-viewport";
    480 
    481 // Enables the use of the legacy viewport meta tag. Turning this on also
    482 // turns on the @viewport CSS rule
    483 const char kEnableViewportMeta[]            = "enable-viewport-meta";
    484 
    485 // Resizes of the main frame are the caused by changing between landscape
    486 // and portrait mode (i.e. Android) so the page should be rescaled to fit
    487 const char kMainFrameResizesAreOrientationChanges[] =
    488     "main-frame-resizes-are-orientation-changes";
    489 
    490 // Enable the Vtune profiler support.
    491 const char kEnableVtune[]                   = "enable-vtune-support";
    492 
    493 // Enables WebGL extensions not yet approved by the community.
    494 const char kEnableWebGLDraftExtensions[] = "enable-webgl-draft-extensions";
    495 
    496 // Enables WebGL rendering into a scanout buffer for overlay support.
    497 const char kEnableWebGLImageChromium[] = "enable-webgl-image-chromium";
    498 
    499 // Enables Web MIDI API.
    500 const char kEnableWebMIDI[]                 = "enable-web-midi";
    501 
    502 // Enable rasterizer that writes directly to GPU memory associated with tiles.
    503 const char kEnableZeroCopy[]                = "enable-zero-copy";
    504 
    505 // Load NPAPI plugins from the specified directory.
    506 const char kExtraPluginDir[]                = "extra-plugin-dir";
    507 
    508 // Some field trials may be randomized in the browser, and the randomly selected
    509 // outcome needs to be propagated to the renderer. For instance, this is used
    510 // to modify histograms recorded in the renderer, or to get the renderer to
    511 // also set of its state (initialize, or not initialize components) to match the
    512 // experiment(s). The option is also useful for forcing field trials when
    513 // testing changes locally. The argument is a list of name and value pairs,
    514 // separated by slashes. See FieldTrialList::CreateTrialsFromString() in
    515 // field_trial.h for details.
    516 const char kForceFieldTrials[]              = "force-fieldtrials";
    517 
    518 // Always use the Skia GPU backend for drawing layer tiles. Only valid with GPU
    519 // accelerated compositing + impl-side painting. Overrides the
    520 // kEnableGpuRasterization flag.
    521 const char kForceGpuRasterization[]        = "force-gpu-rasterization";
    522 
    523 // Force renderer accessibility to be on instead of enabling it on demand when
    524 // a screen reader is detected. The disable-renderer-accessibility switch
    525 // overrides this if present.
    526 const char kForceRendererAccessibility[]    = "force-renderer-accessibility";
    527 
    528 // Passes gpu device_id from browser process to GPU process.
    529 const char kGpuDeviceID[]                   = "gpu-device-id";
    530 
    531 // Passes gpu driver_vendor from browser process to GPU process.
    532 const char kGpuDriverVendor[]               = "gpu-driver-vendor";
    533 
    534 // Passes gpu driver_version from browser process to GPU process.
    535 const char kGpuDriverVersion[]              = "gpu-driver-version";
    536 
    537 // Extra command line options for launching the GPU process (normally used
    538 // for debugging). Use like renderer-cmd-prefix.
    539 const char kGpuLauncher[]                   = "gpu-launcher";
    540 
    541 // Makes this process a GPU sub-process.
    542 const char kGpuProcess[]                    = "gpu-process";
    543 
    544 // Allows shmat() system call in the GPU sandbox.
    545 const char kGpuSandboxAllowSysVShm[]        = "gpu-sandbox-allow-sysv-shm";
    546 
    547 // Makes GPU sandbox failures fatal.
    548 const char kGpuSandboxFailuresFatal[]       = "gpu-sandbox-failures-fatal";
    549 
    550 // Starts the GPU sandbox before creating a GL context.
    551 const char kGpuSandboxStartEarly[]          = "gpu-sandbox-start-early";
    552 
    553 // Causes the GPU process to display a dialog on launch.
    554 const char kGpuStartupDialog[]              = "gpu-startup-dialog";
    555 
    556 // Passes gpu vendor_id from browser process to GPU process.
    557 const char kGpuVendorID[]                   = "gpu-vendor-id";
    558 
    559 // These mappings only apply to the host resolver.
    560 const char kHostResolverRules[]             = "host-resolver-rules";
    561 
    562 // Ignores certificate-related errors.
    563 const char kIgnoreCertificateErrors[]       = "ignore-certificate-errors";
    564 
    565 // Ignores GPU blacklist.
    566 const char kIgnoreGpuBlacklist[]            = "ignore-gpu-blacklist";
    567 
    568 // Run the GPU process as a thread in the browser process.
    569 const char kInProcessGPU[]                  = "in-process-gpu";
    570 
    571 // Overrides the timeout, in seconds, that a child process waits for a
    572 // connection from the browser before killing itself.
    573 const char kIPCConnectionTimeout[]          = "ipc-connection-timeout";
    574 
    575 // Specifies the flags passed to JS engine
    576 const char kJavaScriptFlags[]               = "js-flags";
    577 
    578 // Load an NPAPI plugin from the specified path.
    579 const char kLoadPlugin[]                    = "load-plugin";
    580 
    581 // Logs GPU control list decisions when enforcing blacklist rules.
    582 const char kLogGpuControlListDecisions[]    = "log-gpu-control-list-decisions";
    583 
    584 // Sets the minimum log level. Valid values are from 0 to 3:
    585 // INFO = 0, WARNING = 1, LOG_ERROR = 2, LOG_FATAL = 3.
    586 const char kLoggingLevel[]                  = "log-level";
    587 
    588 // Enables saving net log events to a file and sets the file name to use.
    589 const char kLogNetLog[]                     = "log-net-log";
    590 
    591 // Make plugin processes log their sent and received messages to VLOG(1).
    592 const char kLogPluginMessages[]             = "log-plugin-messages";
    593 
    594 // Sets the width and height above which a composited layer will get tiled.
    595 const char kMaxUntiledLayerHeight[]         = "max-untiled-layer-height";
    596 const char kMaxUntiledLayerWidth[]          = "max-untiled-layer-width";
    597 
    598 // Sample memory usage with high frequency and store the results to the
    599 // Renderer.Memory histogram. Used in memory tests.
    600 const char kMemoryMetrics[]                 = "memory-metrics";
    601 
    602 // Mutes audio sent to the audio device so it is not audible during
    603 // automated testing.
    604 const char kMuteAudio[]                     = "mute-audio";
    605 
    606 // Don't send HTTP-Referer headers.
    607 const char kNoReferrers[]                   = "no-referrers";
    608 
    609 // Disables the sandbox for all process types that are normally sandboxed.
    610 const char kNoSandbox[]                     = "no-sandbox";
    611 
    612 // Number of worker threads used to rasterize content.
    613 const char kNumRasterThreads[]              = "num-raster-threads";
    614 
    615 // Controls the behavior of history navigation in response to horizontal
    616 // overscroll.
    617 // Set the value to '0' to disable.
    618 // Set the value to '1' to enable the behavior where pages slide in and out in
    619 // response to the horizontal overscroll gesture and a screenshot of the target
    620 // page is shown.
    621 // Set the value to '2' to enable the simplified overscroll UI where a
    622 // navigation arrow slides in from the side of the screen in response to the
    623 // horizontal overscroll gesture.
    624 // Defaults to '1'.
    625 const char kOverscrollHistoryNavigation[] =
    626     "overscroll-history-navigation";
    627 
    628 // Specifies a command that should be used to launch the plugin process.  Useful
    629 // for running the plugin process through purify or quantify.  Ex:
    630 //   --plugin-launcher="path\to\purify /Run=yes"
    631 const char kPluginLauncher[]                = "plugin-launcher";
    632 
    633 // Tells the plugin process the path of the plugin to load
    634 const char kPluginPath[]                    = "plugin-path";
    635 
    636 // Causes the process to run as a plugin subprocess.
    637 const char kPluginProcess[]                 = "plugin";
    638 
    639 // Causes the plugin process to display a dialog on launch.
    640 const char kPluginStartupDialog[]           = "plugin-startup-dialog";
    641 
    642 // Argument to the process type that indicates a PPAPI broker process type.
    643 const char kPpapiBrokerProcess[]            = "ppapi-broker";
    644 
    645 // "Command-line" arguments for the PPAPI Flash; used for debugging options.
    646 const char kPpapiFlashArgs[]                = "ppapi-flash-args";
    647 
    648 // Runs PPAPI (Pepper) plugins in-process.
    649 const char kPpapiInProcess[]                = "ppapi-in-process";
    650 
    651 // Like kPluginLauncher for PPAPI plugins.
    652 const char kPpapiPluginLauncher[]           = "ppapi-plugin-launcher";
    653 
    654 // Argument to the process type that indicates a PPAPI plugin process type.
    655 const char kPpapiPluginProcess[]            = "ppapi";
    656 
    657 // Causes the PPAPI sub process to display a dialog on launch. Be sure to use
    658 // --no-sandbox as well or the sandbox won't allow the dialog to display.
    659 const char kPpapiStartupDialog[]            = "ppapi-startup-dialog";
    660 
    661 // Runs a single process for each site (i.e., group of pages from the same
    662 // registered domain) the user visits.  We default to using a renderer process
    663 // for each site instance (i.e., group of pages from the same registered
    664 // domain with script connections to each other).
    665 const char kProcessPerSite[]                = "process-per-site";
    666 
    667 // Runs each set of script-connected tabs (i.e., a BrowsingInstance) in its own
    668 // renderer process.  We default to using a renderer process for each
    669 // site instance (i.e., group of pages from the same registered domain with
    670 // script connections to each other).
    671 const char kProcessPerTab[]                 = "process-per-tab";
    672 
    673 // The value of this switch determines whether the process is started as a
    674 // renderer or plugin host.  If it's empty, it's the browser.
    675 const char kProcessType[]                   = "type";
    676 
    677 // Enables more web features over insecure connections. Designed to be used
    678 // for testing purposes only.
    679 const char kReduceSecurityForTesting[]      = "reduce-security-for-testing";
    680 
    681 // Register Pepper plugins (see pepper_plugin_list.cc for its format).
    682 const char kRegisterPepperPlugins[]         = "register-pepper-plugins";
    683 
    684 // Enables remote debug over HTTP on the specified port.
    685 const char kRemoteDebuggingPort[]           = "remote-debugging-port";
    686 
    687 // Causes the renderer process to throw an assertion on launch.
    688 const char kRendererAssertTest[]            = "renderer-assert-test";
    689 
    690 // On POSIX only: the contents of this flag are prepended to the renderer
    691 // command line. Useful values might be "valgrind" or "xterm -e gdb --args".
    692 const char kRendererCmdPrefix[]             = "renderer-cmd-prefix";
    693 
    694 // Causes the process to run as renderer instead of as browser.
    695 const char kRendererProcess[]               = "renderer";
    696 
    697 // Overrides the default/calculated limit to the number of renderer processes.
    698 // Very high values for this setting can lead to high memory/resource usage
    699 // or instability.
    700 const char kRendererProcessLimit[]          = "renderer-process-limit";
    701 
    702 // Causes the renderer process to display a dialog on launch.
    703 const char kRendererStartupDialog[]         = "renderer-startup-dialog";
    704 
    705 // Causes the process to run as a sandbox IPC subprocess.
    706 const char kSandboxIPCProcess[]             = "sandbox-ipc";
    707 
    708 // Enables or disables scroll end effect in response to vertical overscroll.
    709 // Set the value to '1' to enable the feature, and set to '0' to disable.
    710 // Defaults to disabled.
    711 const char kScrollEndEffect[] = "scroll-end-effect";
    712 
    713 // Visibly render a border around paint rects in the web page to help debug
    714 // and study painting behavior.
    715 const char kShowPaintRects[]                = "show-paint-rects";
    716 
    717 // Runs the renderer and plugins in the same process as the browser
    718 const char kSingleProcess[]                 = "single-process";
    719 
    720 // Experimentally enforces a one-site-per-process security policy.
    721 // All cross-site navigations force process swaps, and we can restrict a
    722 // renderer process's access rights based on its site.  For details, see:
    723 // http://www.chromium.org/developers/design-documents/site-isolation
    724 //
    725 // Unlike --enable-strict-site-isolation (which allows cross-site iframes),
    726 // this flag does not affect which cookies are attached to cross-site requests.
    727 // Support is being added to render cross-site iframes in a different process
    728 // than their parent pages.
    729 const char kSitePerProcess[]                = "site-per-process";
    730 
    731 // Skip gpu info collection, blacklist loading, and blacklist auto-update
    732 // scheduling at browser startup time.
    733 // Therefore, all GPU features are available, and about:gpu page shows empty
    734 // content. The switch is intended only for layout tests.
    735 // TODO(gab): Get rid of this switch entirely.
    736 const char kSkipGpuDataLoading[]            = "skip-gpu-data-loading";
    737 
    738 // Specifies if the browser should start in fullscreen mode, like if the user
    739 // had pressed F11 right after startup.
    740 const char kStartFullscreen[] = "start-fullscreen";
    741 
    742 // Specifies if the |StatsCollectionController| needs to be bound in the
    743 // renderer. This binding happens on per-frame basis and hence can potentially
    744 // be a performance bottleneck. One should only enable it when running a test
    745 // that needs to access the provided statistics.
    746 const char kStatsCollectionController[] =
    747     "enable-stats-collection-bindings";
    748 
    749 // Upscale defaults to "good".
    750 const char kTabCaptureDownscaleQuality[]    = "tab-capture-downscale-quality";
    751 
    752 // Scaling quality for capturing tab. Should be one of "fast", "good" or "best".
    753 // One flag for upscaling, one for downscaling.
    754 // Upscale defaults to "best".
    755 const char kTabCaptureUpscaleQuality[]      = "tab-capture-upscale-quality";
    756 
    757 // Allows for forcing socket connections to http/https to use fixed ports.
    758 const char kTestingFixedHttpPort[]          = "testing-fixed-http-port";
    759 const char kTestingFixedHttpsPort[]         = "testing-fixed-https-port";
    760 
    761 // Type of the current test harness ("browser" or "ui").
    762 const char kTestType[]                      = "test-type";
    763 
    764 const char kTouchScrollingMode[]            = "touch-scrolling-mode";
    765 const char kTouchScrollingModeAsyncTouchmove[] = "async-touchmove";
    766 const char kTouchScrollingModeSyncTouchmove[] = "sync-touchmove";
    767 const char kTouchScrollingModeTouchcancel[] = "touchcancel";
    768 
    769 // Causes TRACE_EVENT flags to be recorded beginning with shutdown. Optionally,
    770 // can specify the specific trace categories to include (e.g.
    771 // --trace-shutdown=base,net) otherwise, all events are recorded.
    772 // --trace-shutdown-file can be used to control where the trace log gets stored
    773 // to since there is otherwise no way to access the result.
    774 const char kTraceShutdown[]                 = "trace-shutdown";
    775 
    776 // If supplied, sets the file which shutdown tracing will be stored into, if
    777 // omitted the default will be used "chrometrace.log" in the current directory.
    778 // Has no effect unless --trace-shutdown is also supplied.
    779 // Example: --trace-shutdown --trace-shutdown-file=/tmp/trace_event.log
    780 const char kTraceShutdownFile[]             = "trace-shutdown-file";
    781 
    782 // Causes TRACE_EVENT flags to be recorded from startup. Optionally, can
    783 // specify the specific trace categories to include (e.g.
    784 // --trace-startup=base,net) otherwise, all events are recorded. Setting this
    785 // flag results in the first call to BeginTracing() to receive all trace events
    786 // since startup. In Chrome, you may find --trace-startup-file and
    787 // --trace-startup-duration to control the auto-saving of the trace (not
    788 // supported in the base-only TraceLog component).
    789 const char kTraceStartup[]                  = "trace-startup";
    790 
    791 // Sets the time in seconds until startup tracing ends. If omitted a default of
    792 // 5 seconds is used. Has no effect without --trace-startup, or if
    793 // --startup-trace-file=none was supplied.
    794 const char kTraceStartupDuration[]          = "trace-startup-duration";
    795 
    796 // If supplied, sets the file which startup tracing will be stored into, if
    797 // omitted the default will be used "chrometrace.log" in the current directory.
    798 // Has no effect unless --trace-startup is also supplied.
    799 // Example: --trace-startup --trace-startup-file=/tmp/trace_event.log
    800 // As a special case, can be set to 'none' - this disables automatically saving
    801 // the result to a file and the first manually recorded trace will then receive
    802 // all events since startup.
    803 const char kTraceStartupFile[]              = "trace-startup-file";
    804 
    805 // Sets the target URL for uploading tracing data.
    806 const char kTraceUploadURL[]                = "trace-upload-url";
    807 
    808 
    809 // Prioritizes the UI's command stream in the GPU process
    810 extern const char kUIPrioritizeInGpuProcess[] =
    811     "ui-prioritize-in-gpu-process";
    812 
    813 // Overrides the preferred discardable memory implementation.
    814 const char kUseDiscardableMemory[] = "use-discardable-memory";
    815 
    816 // Bypass the media stream infobar by selecting the default device for media
    817 // streams (e.g. WebRTC). Works with --use-fake-device-for-media-stream.
    818 const char kUseFakeUIForMediaStream[]     = "use-fake-ui-for-media-stream";
    819 
    820 // Set when Chromium should use a mobile user agent.
    821 const char kUseMobileUserAgent[] = "use-mobile-user-agent";
    822 
    823 // Use the new surfaces system to handle compositor delegation.
    824 const char kUseSurfaces[] = "use-surfaces";
    825 
    826 // On POSIX only: the contents of this flag are prepended to the utility
    827 // process command line. Useful values might be "valgrind" or "xterm -e gdb
    828 // --args".
    829 const char kUtilityCmdPrefix[]              = "utility-cmd-prefix";
    830 
    831 // Causes the process to run as a utility subprocess.
    832 const char kUtilityProcess[]                = "utility";
    833 
    834 // The utility process is sandboxed, with access to one directory. This flag
    835 // specifies the directory that can be accessed.
    836 const char kUtilityProcessAllowedDir[]      = "utility-allowed-dir";
    837 
    838 // Allows MDns to access network in sandboxed process.
    839 const char kUtilityProcessEnableMDns[]      = "utility-enable-mdns";
    840 
    841 const char kUtilityProcessRunningElevated[] = "utility-run-elevated";
    842 
    843 // In debug builds, asserts that the stream of input events is valid.
    844 const char kValidateInputEventStream[] = "validate-input-event-stream";
    845 
    846 // Will add kWaitForDebugger to every child processes. If a value is passed, it
    847 // will be used as a filter to determine if the child process should have the
    848 // kWaitForDebugger flag passed on or not.
    849 const char kWaitForDebuggerChildren[]       = "wait-for-debugger-children";
    850 
    851 // The prefix used when starting the zygote process. (i.e. 'gdb --args')
    852 const char kZygoteCmdPrefix[]               = "zygote-cmd-prefix";
    853 
    854 // Causes the process to run as a renderer zygote.
    855 const char kZygoteProcess[]                 = "zygote";
    856 
    857 #if defined(ENABLE_WEBRTC)
    858 // Disables audio processing in a MediaStreamTrack. When this flag is on, AEC,
    859 // NS and AGC will be done in PeerConnection instead of MediaStreamTrack.
    860 const char kDisableAudioTrackProcessing[]    = "disable-audio-track-processing";
    861 
    862 // Disables HW decode acceleration for WebRTC.
    863 const char kDisableWebRtcHWDecoding[]       = "disable-webrtc-hw-decoding";
    864 
    865 // Disables encryption of RTP Media for WebRTC. When Chrome embeds Content, it
    866 // ignores this switch on its stable and beta channels.
    867 const char kDisableWebRtcEncryption[]      = "disable-webrtc-encryption";
    868 
    869 // Disables HW encode acceleration for WebRTC.
    870 const char kDisableWebRtcHWEncoding[]       = "disable-webrtc-hw-encoding";
    871 
    872 // Enables VP8 HW encode acceleration for WebRTC.
    873 const char kEnableWebRtcHWVp8Encoding[]     = "enable-webrtc-hw-vp8-encoding";
    874 
    875 // Enables H264 HW encode acceleration for WebRTC.
    876 const char kEnableWebRtcHWH264Encoding[]    = "enable-webrtc-hw-h264-encoding";
    877 #endif
    878 
    879 #if defined(OS_ANDROID)
    880 // Disable user gesture requirement for media playback.
    881 const char kDisableGestureRequirementForMediaPlayback[] =
    882     "disable-gesture-requirement-for-media-playback";
    883 
    884 // Disable the click delay by sending click events during double tap.
    885 const char kDisableClickDelay[]             = "disable-click-delay";
    886 
    887 // Disable overscroll edge effects like those found in Android views.
    888 const char kDisableOverscrollEdgeEffect[]   = "disable-overscroll-edge-effect";
    889 
    890 // WebRTC is enabled by default on Android.
    891 const char kDisableWebRTC[]                 = "disable-webrtc";
    892 
    893 // Enable the PowerSaveBlocker in ContentVideoView. Android only.
    894 const char kEnableContentVideoViewPowerSaveBlocker[] =
    895     "enable-content-video-view-power-save-blocker";
    896 
    897 // Enable the recognition part of the Web Speech API.
    898 const char kEnableSpeechRecognition[]       = "enable-speech-recognition";
    899 
    900 // Always use the video overlay for the embedded video.
    901 // This switch is intended only for tests.
    902 const char kForceUseOverlayEmbeddedVideo[] = "force-use-overlay-embedded-video";
    903 
    904 // The telephony region (ISO country code) to use in phone number detection.
    905 const char kNetworkCountryIso[] = "network-country-iso";
    906 
    907 // Enables remote debug over HTTP on the specified socket name.
    908 const char kRemoteDebuggingSocketName[]     = "remote-debugging-socket-name";
    909 
    910 // Block ChildProcessMain thread of the renderer's ChildProcessService until a
    911 // Java debugger is attached.
    912 const char kRendererWaitForJavaDebugger[] = "renderer-wait-for-java-debugger";
    913 #endif
    914 
    915 // Disable web audio API.
    916 const char kDisableWebAudio[]               = "disable-webaudio";
    917 
    918 #if defined(OS_CHROMEOS)
    919 // Disables panel fitting (used for mirror mode).
    920 const char kDisablePanelFitting[]           = "disable-panel-fitting";
    921 
    922 // Enables VA-API accelerated video encode.
    923 const char kDisableVaapiAcceleratedVideoEncode[] =
    924     "disable-vaapi-accelerated-video-encode";
    925 #endif
    926 
    927 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
    928 // Allows sending text-to-speech requests to speech-dispatcher, a common
    929 // Linux speech service. Because it's buggy, the user must explicitly
    930 // enable it so that visiting a random webpage can't cause instability.
    931 const char kEnableSpeechDispatcher[] = "enable-speech-dispatcher";
    932 #endif
    933 
    934 #if defined(OS_MACOSX) && !defined(OS_IOS)
    935 // Disables support for Core Animation plugins. This is triggered when
    936 // accelerated compositing is disabled. See http://crbug.com/122430 .
    937 const char kDisableCoreAnimationPlugins[] =
    938     "disable-core-animation-plugins";
    939 #endif
    940 
    941 #if defined(OS_WIN)
    942 // Device scale factor passed to certain processes like renderers, etc.
    943 const char kDeviceScaleFactor[]     = "device-scale-factor";
    944 
    945 // Disables the DirectWrite font rendering system on windows.
    946 const char kDisableDirectWrite[]             = "disable-direct-write";
    947 
    948 // Disable the Legacy Window which corresponds to the size of the WebContents.
    949 const char kDisableLegacyIntermediateWindow[] = "disable-legacy-window";
    950 
    951 // Enable the Win32K process mitigation policy for renderer processes which
    952 // prevents them from invoking user32 and gdi32 system calls which enter
    953 // the kernel. This is only supported on Windows 8 and beyond.
    954 const char kEnableWin32kRendererLockDown[]
    955     = "enable_win32k_renderer_lockdown";
    956 #endif
    957 
    958 // Don't dump stuff here, follow the same order as the header.
    959 
    960 }  // namespace switches
    961