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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 #ifndef CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_
      6 #define CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_
      7 
      8 #include <string>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "content/common/content_export.h"
     13 
     14 namespace content {
     15 
     16 // A RAII-style class to block the system from entering low-power (sleep) mode.
     17 // This class is thread-safe; it may be constructed and deleted on any thread.
     18 class CONTENT_EXPORT PowerSaveBlocker {
     19  public:
     20   enum PowerSaveBlockerType {
     21     // Prevent the application from being suspended. On some platforms, apps may
     22     // be suspended when they are not visible to the user. This type of block
     23     // requests that the app continue to run in that case, and on all platforms
     24     // prevents the system from sleeping.
     25     // Example use cases: downloading a file, playing audio.
     26     kPowerSaveBlockPreventAppSuspension,
     27 
     28     // Prevent the display from going to sleep. This also has the side effect of
     29     // preventing the system from sleeping, but does not necessarily prevent the
     30     // app from being suspended on some platforms if the user hides it.
     31     // Example use case: playing video.
     32     kPowerSaveBlockPreventDisplaySleep,
     33   };
     34 
     35   virtual ~PowerSaveBlocker() = 0;
     36 
     37   // Pass in the type of power save blocking desired. If multiple types of
     38   // blocking are desired, instantiate one PowerSaveBlocker for each type.
     39   // |reason| may be provided to the underlying system APIs on some platforms.
     40   static scoped_ptr<PowerSaveBlocker> Create(PowerSaveBlockerType type,
     41                                              const std::string& reason);
     42 };
     43 
     44 }  // namespace content
     45 
     46 #endif  // CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_
     47