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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License
     15  */
     16 
     17 package com.android.server.wm;
     18 
     19 import static android.app.WindowConfiguration.ACTIVITY_TYPE_STANDARD;
     20 import static android.app.WindowConfiguration.WINDOWING_MODE_PINNED;
     21 import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE;
     22 import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_PORTRAIT;
     23 import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED;
     24 import static android.view.Display.DEFAULT_DISPLAY;
     25 import static android.view.DisplayCutout.fromBoundingRect;
     26 import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION;
     27 import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION_ATTACHED_DIALOG;
     28 import static android.view.WindowManager.LayoutParams.TYPE_BASE_APPLICATION;
     29 import static android.view.WindowManager.LayoutParams.TYPE_STATUS_BAR;
     30 import static android.view.WindowManager.LayoutParams.TYPE_VOICE_INTERACTION;
     31 import static com.android.server.wm.WindowContainer.POSITION_TOP;
     32 
     33 import static org.hamcrest.Matchers.is;
     34 import static org.junit.Assert.assertEquals;
     35 import static org.junit.Assert.assertFalse;
     36 import static org.junit.Assert.assertThat;
     37 import static org.junit.Assert.assertTrue;
     38 import static org.mockito.Mockito.times;
     39 import static org.mockito.Mockito.verify;
     40 
     41 import org.junit.Test;
     42 import org.junit.runner.RunWith;
     43 
     44 import android.annotation.SuppressLint;
     45 import android.content.res.Configuration;
     46 import android.graphics.Rect;
     47 import android.os.SystemClock;
     48 import android.platform.test.annotations.Presubmit;
     49 import android.support.test.filters.FlakyTest;
     50 import android.support.test.filters.SmallTest;
     51 import android.support.test.runner.AndroidJUnit4;
     52 import android.util.DisplayMetrics;
     53 import android.util.SparseIntArray;
     54 import android.view.DisplayCutout;
     55 import android.view.MotionEvent;
     56 import android.view.Surface;
     57 
     58 import com.android.server.wm.utils.WmDisplayCutout;
     59 
     60 import java.util.ArrayList;
     61 import java.util.Arrays;
     62 import java.util.Collections;
     63 import java.util.LinkedList;
     64 import java.util.List;
     65 
     66 /**
     67  * Tests for the {@link DisplayContent} class.
     68  *
     69  * Build/Install/Run:
     70  *  atest com.android.server.wm.DisplayContentTests
     71  */
     72 @SmallTest
     73 @Presubmit
     74 @RunWith(AndroidJUnit4.class)
     75 public class DisplayContentTests extends WindowTestsBase {
     76 
     77     @Test
     78     @FlakyTest(bugId = 77772044)
     79     public void testForAllWindows() throws Exception {
     80         final WindowState exitingAppWindow = createWindow(null, TYPE_BASE_APPLICATION,
     81                 mDisplayContent, "exiting app");
     82         final AppWindowToken exitingAppToken = exitingAppWindow.mAppToken;
     83         exitingAppToken.mIsExiting = true;
     84         exitingAppToken.getTask().mStack.mExitingAppTokens.add(exitingAppToken);
     85 
     86         assertForAllWindowsOrder(Arrays.asList(
     87                 mWallpaperWindow,
     88                 exitingAppWindow,
     89                 mChildAppWindowBelow,
     90                 mAppWindow,
     91                 mChildAppWindowAbove,
     92                 mDockedDividerWindow,
     93                 mStatusBarWindow,
     94                 mNavBarWindow,
     95                 mImeWindow,
     96                 mImeDialogWindow));
     97     }
     98 
     99     @Test
    100     public void testForAllWindows_WithAppImeTarget() throws Exception {
    101         final WindowState imeAppTarget =
    102                 createWindow(null, TYPE_BASE_APPLICATION, mDisplayContent, "imeAppTarget");
    103 
    104         sWm.mInputMethodTarget = imeAppTarget;
    105 
    106         assertForAllWindowsOrder(Arrays.asList(
    107                 mWallpaperWindow,
    108                 mChildAppWindowBelow,
    109                 mAppWindow,
    110                 mChildAppWindowAbove,
    111                 imeAppTarget,
    112                 mImeWindow,
    113                 mImeDialogWindow,
    114                 mDockedDividerWindow,
    115                 mStatusBarWindow,
    116                 mNavBarWindow));
    117     }
    118 
    119     @Test
    120     public void testForAllWindows_WithChildWindowImeTarget() throws Exception {
    121         sWm.mInputMethodTarget = mChildAppWindowAbove;
    122 
    123         assertForAllWindowsOrder(Arrays.asList(
    124                 mWallpaperWindow,
    125                 mChildAppWindowBelow,
    126                 mAppWindow,
    127                 mChildAppWindowAbove,
    128                 mImeWindow,
    129                 mImeDialogWindow,
    130                 mDockedDividerWindow,
    131                 mStatusBarWindow,
    132                 mNavBarWindow));
    133     }
    134 
    135     @Test
    136     public void testForAllWindows_WithStatusBarImeTarget() throws Exception {
    137         sWm.mInputMethodTarget = mStatusBarWindow;
    138 
    139         assertForAllWindowsOrder(Arrays.asList(
    140                 mWallpaperWindow,
    141                 mChildAppWindowBelow,
    142                 mAppWindow,
    143                 mChildAppWindowAbove,
    144                 mDockedDividerWindow,
    145                 mStatusBarWindow,
    146                 mImeWindow,
    147                 mImeDialogWindow,
    148                 mNavBarWindow));
    149     }
    150 
    151     @Test
    152     public void testForAllWindows_WithInBetweenWindowToken() throws Exception {
    153         // This window is set-up to be z-ordered between some windows that go in the same token like
    154         // the nav bar and status bar.
    155         final WindowState voiceInteractionWindow = createWindow(null, TYPE_VOICE_INTERACTION,
    156                 mDisplayContent, "voiceInteractionWindow");
    157 
    158         assertForAllWindowsOrder(Arrays.asList(
    159                 mWallpaperWindow,
    160                 mChildAppWindowBelow,
    161                 mAppWindow,
    162                 mChildAppWindowAbove,
    163                 mDockedDividerWindow,
    164                 voiceInteractionWindow,
    165                 mStatusBarWindow,
    166                 mNavBarWindow,
    167                 mImeWindow,
    168                 mImeDialogWindow));
    169     }
    170 
    171     @Test
    172     public void testComputeImeTarget() throws Exception {
    173         // Verify that an app window can be an ime target.
    174         final WindowState appWin = createWindow(null, TYPE_APPLICATION, mDisplayContent, "appWin");
    175         appWin.setHasSurface(true);
    176         assertTrue(appWin.canBeImeTarget());
    177         WindowState imeTarget = mDisplayContent.computeImeTarget(false /* updateImeTarget */);
    178         assertEquals(appWin, imeTarget);
    179         appWin.mHidden = false;
    180 
    181         // Verify that an child window can be an ime target.
    182         final WindowState childWin = createWindow(appWin,
    183                 TYPE_APPLICATION_ATTACHED_DIALOG, "childWin");
    184         childWin.setHasSurface(true);
    185         assertTrue(childWin.canBeImeTarget());
    186         imeTarget = mDisplayContent.computeImeTarget(false /* updateImeTarget */);
    187         assertEquals(childWin, imeTarget);
    188     }
    189 
    190     /**
    191      * This tests stack movement between displays and proper stack's, task's and app token's display
    192      * container references updates.
    193      */
    194     @Test
    195     public void testMoveStackBetweenDisplays() throws Exception {
    196         // Create a second display.
    197         final DisplayContent dc = createNewDisplay();
    198 
    199         // Add stack with activity.
    200         final TaskStack stack = createTaskStackOnDisplay(dc);
    201         assertEquals(dc.getDisplayId(), stack.getDisplayContent().getDisplayId());
    202         assertEquals(dc, stack.getParent().getParent());
    203         assertEquals(dc, stack.getDisplayContent());
    204 
    205         final Task task = createTaskInStack(stack, 0 /* userId */);
    206         final WindowTestUtils.TestAppWindowToken token = WindowTestUtils.createTestAppWindowToken(
    207                 dc);
    208         task.addChild(token, 0);
    209         assertEquals(dc, task.getDisplayContent());
    210         assertEquals(dc, token.getDisplayContent());
    211 
    212         // Move stack to first display.
    213         mDisplayContent.moveStackToDisplay(stack, true /* onTop */);
    214         assertEquals(mDisplayContent.getDisplayId(), stack.getDisplayContent().getDisplayId());
    215         assertEquals(mDisplayContent, stack.getParent().getParent());
    216         assertEquals(mDisplayContent, stack.getDisplayContent());
    217         assertEquals(mDisplayContent, task.getDisplayContent());
    218         assertEquals(mDisplayContent, token.getDisplayContent());
    219     }
    220 
    221     /**
    222      * This tests override configuration updates for display content.
    223      */
    224     @Test
    225     public void testDisplayOverrideConfigUpdate() throws Exception {
    226         final int displayId = mDisplayContent.getDisplayId();
    227         final Configuration currentOverrideConfig = mDisplayContent.getOverrideConfiguration();
    228 
    229         // Create new, slightly changed override configuration and apply it to the display.
    230         final Configuration newOverrideConfig = new Configuration(currentOverrideConfig);
    231         newOverrideConfig.densityDpi += 120;
    232         newOverrideConfig.fontScale += 0.3;
    233 
    234         sWm.setNewDisplayOverrideConfiguration(newOverrideConfig, displayId);
    235 
    236         // Check that override config is applied.
    237         assertEquals(newOverrideConfig, mDisplayContent.getOverrideConfiguration());
    238     }
    239 
    240     /**
    241      * This tests global configuration updates when default display config is updated.
    242      */
    243     @Test
    244     public void testDefaultDisplayOverrideConfigUpdate() throws Exception {
    245         final Configuration currentConfig = mDisplayContent.getConfiguration();
    246 
    247         // Create new, slightly changed override configuration and apply it to the display.
    248         final Configuration newOverrideConfig = new Configuration(currentConfig);
    249         newOverrideConfig.densityDpi += 120;
    250         newOverrideConfig.fontScale += 0.3;
    251 
    252         sWm.setNewDisplayOverrideConfiguration(newOverrideConfig, DEFAULT_DISPLAY);
    253 
    254         // Check that global configuration is updated, as we've updated default display's config.
    255         Configuration globalConfig = sWm.mRoot.getConfiguration();
    256         assertEquals(newOverrideConfig.densityDpi, globalConfig.densityDpi);
    257         assertEquals(newOverrideConfig.fontScale, globalConfig.fontScale, 0.1 /* delta */);
    258 
    259         // Return back to original values.
    260         sWm.setNewDisplayOverrideConfiguration(currentConfig, DEFAULT_DISPLAY);
    261         globalConfig = sWm.mRoot.getConfiguration();
    262         assertEquals(currentConfig.densityDpi, globalConfig.densityDpi);
    263         assertEquals(currentConfig.fontScale, globalConfig.fontScale, 0.1 /* delta */);
    264     }
    265 
    266     /**
    267      * Tests tapping on a stack in different display results in window gaining focus.
    268      */
    269     @Test
    270     public void testInputEventBringsCorrectDisplayInFocus() throws Exception {
    271         DisplayContent dc0 = sWm.getDefaultDisplayContentLocked();
    272         // Create a second display
    273         final DisplayContent dc1 = createNewDisplay();
    274 
    275         // Add stack with activity.
    276         final TaskStack stack0 = createTaskStackOnDisplay(dc0);
    277         final Task task0 = createTaskInStack(stack0, 0 /* userId */);
    278         final WindowTestUtils.TestAppWindowToken token =
    279                 WindowTestUtils.createTestAppWindowToken(dc0);
    280         task0.addChild(token, 0);
    281         dc0.mTapDetector = new TaskTapPointerEventListener(sWm, dc0);
    282         sWm.registerPointerEventListener(dc0.mTapDetector);
    283         final TaskStack stack1 = createTaskStackOnDisplay(dc1);
    284         final Task task1 = createTaskInStack(stack1, 0 /* userId */);
    285         final WindowTestUtils.TestAppWindowToken token1 =
    286                 WindowTestUtils.createTestAppWindowToken(dc0);
    287         task1.addChild(token1, 0);
    288         dc1.mTapDetector = new TaskTapPointerEventListener(sWm, dc0);
    289         sWm.registerPointerEventListener(dc1.mTapDetector);
    290 
    291         // tap on primary display (by sending ACTION_DOWN followed by ACTION_UP)
    292         DisplayMetrics dm0 = dc0.getDisplayMetrics();
    293         dc0.mTapDetector.onPointerEvent(
    294                 createTapEvent(dm0.widthPixels / 2, dm0.heightPixels / 2, true));
    295         dc0.mTapDetector.onPointerEvent(
    296                 createTapEvent(dm0.widthPixels / 2, dm0.heightPixels / 2, false));
    297 
    298         // Check focus is on primary display.
    299         assertEquals(sWm.mCurrentFocus, dc0.findFocusedWindow());
    300 
    301         // Tap on secondary display
    302         DisplayMetrics dm1 = dc1.getDisplayMetrics();
    303         dc1.mTapDetector.onPointerEvent(
    304                 createTapEvent(dm1.widthPixels / 2, dm1.heightPixels / 2, true));
    305         dc1.mTapDetector.onPointerEvent(
    306                 createTapEvent(dm1.widthPixels / 2, dm1.heightPixels / 2, false));
    307 
    308         // Check focus is on secondary.
    309         assertEquals(sWm.mCurrentFocus, dc1.findFocusedWindow());
    310     }
    311 
    312     @Test
    313     public void testFocusedWindowMultipleDisplays() throws Exception {
    314         // Create a focusable window and check that focus is calculated correctly
    315         final WindowState window1 =
    316                 createWindow(null, TYPE_BASE_APPLICATION, mDisplayContent, "window1");
    317         assertEquals(window1, sWm.mRoot.computeFocusedWindow());
    318 
    319         // Check that a new display doesn't affect focus
    320         final DisplayContent dc = createNewDisplay();
    321         assertEquals(window1, sWm.mRoot.computeFocusedWindow());
    322 
    323         // Add a window to the second display, and it should be focused
    324         final WindowState window2 = createWindow(null, TYPE_BASE_APPLICATION, dc, "window2");
    325         assertEquals(window2, sWm.mRoot.computeFocusedWindow());
    326 
    327         // Move the first window to the to including parents, and make sure focus is updated
    328         window1.getParent().positionChildAt(POSITION_TOP, window1, true);
    329         assertEquals(window1, sWm.mRoot.computeFocusedWindow());
    330     }
    331 
    332     @Test
    333     public void testKeyguard_preventsSecondaryDisplayFocus() throws Exception {
    334         final WindowState keyguard = createWindow(null, TYPE_STATUS_BAR,
    335                 sWm.getDefaultDisplayContentLocked(), "keyguard");
    336         assertEquals(keyguard, sWm.mRoot.computeFocusedWindow());
    337 
    338         // Add a window to a second display, and it should be focused
    339         final DisplayContent dc = createNewDisplay();
    340         final WindowState win = createWindow(null, TYPE_BASE_APPLICATION, dc, "win");
    341         assertEquals(win, sWm.mRoot.computeFocusedWindow());
    342 
    343         mWmRule.getWindowManagerPolicy().keyguardShowingAndNotOccluded = true;
    344         assertEquals(keyguard, sWm.mRoot.computeFocusedWindow());
    345     }
    346 
    347     /**
    348      * This tests setting the maximum ui width on a display.
    349      */
    350     @Test
    351     public void testMaxUiWidth() throws Exception {
    352         final int baseWidth = 1440;
    353         final int baseHeight = 2560;
    354         final int baseDensity = 300;
    355 
    356         mDisplayContent.updateBaseDisplayMetrics(baseWidth, baseHeight, baseDensity);
    357 
    358         final int maxWidth = 300;
    359         final int resultingHeight = (maxWidth * baseHeight) / baseWidth;
    360         final int resultingDensity = (maxWidth * baseDensity) / baseWidth;
    361 
    362         mDisplayContent.setMaxUiWidth(maxWidth);
    363         verifySizes(mDisplayContent, maxWidth, resultingHeight, resultingDensity);
    364 
    365         // Assert setting values again does not change;
    366         mDisplayContent.updateBaseDisplayMetrics(baseWidth, baseHeight, baseDensity);
    367         verifySizes(mDisplayContent, maxWidth, resultingHeight, resultingDensity);
    368 
    369         final int smallerWidth = 200;
    370         final int smallerHeight = 400;
    371         final int smallerDensity = 100;
    372 
    373         // Specify smaller dimension, verify that it is honored
    374         mDisplayContent.updateBaseDisplayMetrics(smallerWidth, smallerHeight, smallerDensity);
    375         verifySizes(mDisplayContent, smallerWidth, smallerHeight, smallerDensity);
    376 
    377         // Verify that setting the max width to a greater value than the base width has no effect
    378         mDisplayContent.setMaxUiWidth(maxWidth);
    379         verifySizes(mDisplayContent, smallerWidth, smallerHeight, smallerDensity);
    380     }
    381 
    382     /**
    383      * This test enforces that the pinned stack is always kept as the top stack.
    384      */
    385     @Test
    386     public void testPinnedStackLocation() {
    387         final TaskStack pinnedStack = createStackControllerOnStackOnDisplay(
    388                 WINDOWING_MODE_PINNED, ACTIVITY_TYPE_STANDARD, mDisplayContent).mContainer;
    389         // Ensure that the pinned stack is the top stack
    390         assertEquals(pinnedStack, mDisplayContent.getPinnedStack());
    391         assertEquals(pinnedStack, mDisplayContent.getTopStack());
    392         // By default, this should try to create a new stack on top
    393         final TaskStack otherStack = createTaskStackOnDisplay(mDisplayContent);
    394         // Ensure that the other stack is on the display.
    395         assertEquals(mDisplayContent, otherStack.getDisplayContent());
    396         // Ensure that the pinned stack is still on top
    397         assertEquals(pinnedStack, mDisplayContent.getTopStack());
    398     }
    399 
    400     /**
    401      * Test that WM does not report displays to AM that are pending to be removed.
    402      */
    403     @Test
    404     public void testDontReportDeferredRemoval() {
    405         // Create a display and add an animating window to it.
    406         final DisplayContent dc = createNewDisplay();
    407         final WindowState window = createWindow(null /* parent */, TYPE_BASE_APPLICATION, dc, "w");
    408         window.mAnimatingExit = true;
    409         // Request display removal, it should be deferred.
    410         dc.removeIfPossible();
    411         // Request ordered display ids from WM.
    412         final SparseIntArray orderedDisplayIds = new SparseIntArray();
    413         sWm.getDisplaysInFocusOrder(orderedDisplayIds);
    414         // Make sure that display that is marked for removal is not reported.
    415         assertEquals(-1, orderedDisplayIds.indexOfValue(dc.getDisplayId()));
    416     }
    417 
    418     @Test
    419     public void testDisplayCutout_rot0() throws Exception {
    420         synchronized (sWm.getWindowManagerLock()) {
    421             final DisplayContent dc = createNewDisplay();
    422             dc.mInitialDisplayWidth = 200;
    423             dc.mInitialDisplayHeight = 400;
    424             Rect r = new Rect(80, 0, 120, 10);
    425             final DisplayCutout cutout = new WmDisplayCutout(
    426                     fromBoundingRect(r.left, r.top, r.right, r.bottom), null)
    427                     .computeSafeInsets(200, 400).getDisplayCutout();
    428 
    429             dc.mInitialDisplayCutout = cutout;
    430             dc.setRotation(Surface.ROTATION_0);
    431             dc.computeScreenConfiguration(new Configuration()); // recomputes dc.mDisplayInfo.
    432 
    433             assertEquals(cutout, dc.getDisplayInfo().displayCutout);
    434         }
    435     }
    436 
    437     @Test
    438     public void testDisplayCutout_rot90() throws Exception {
    439         synchronized (sWm.getWindowManagerLock()) {
    440             final DisplayContent dc = createNewDisplay();
    441             dc.mInitialDisplayWidth = 200;
    442             dc.mInitialDisplayHeight = 400;
    443             Rect r1 = new Rect(80, 0, 120, 10);
    444             final DisplayCutout cutout = new WmDisplayCutout(
    445                     fromBoundingRect(r1.left, r1.top, r1.right, r1.bottom), null)
    446                     .computeSafeInsets(200, 400).getDisplayCutout();
    447 
    448             dc.mInitialDisplayCutout = cutout;
    449             dc.setRotation(Surface.ROTATION_90);
    450             dc.computeScreenConfiguration(new Configuration()); // recomputes dc.mDisplayInfo.
    451 
    452             final Rect r = new Rect(0, 80, 10, 120);
    453             assertEquals(new WmDisplayCutout(
    454                     fromBoundingRect(r.left, r.top, r.right, r.bottom), null)
    455                     .computeSafeInsets(400, 200).getDisplayCutout(), dc.getDisplayInfo().displayCutout);
    456         }
    457     }
    458 
    459     @Test
    460     public void testLayoutSeq_assignedDuringLayout() throws Exception {
    461         synchronized (sWm.getWindowManagerLock()) {
    462 
    463             final DisplayContent dc = createNewDisplay();
    464             final WindowState win = createWindow(null /* parent */, TYPE_BASE_APPLICATION, dc, "w");
    465 
    466             dc.setLayoutNeeded();
    467             dc.performLayout(true /* initial */, false /* updateImeWindows */);
    468 
    469             assertThat(win.mLayoutSeq, is(dc.mLayoutSeq));
    470         }
    471     }
    472 
    473     @Test
    474     @SuppressLint("InlinedApi")
    475     public void testOrientationDefinedByKeyguard() {
    476         final DisplayContent dc = createNewDisplay();
    477         // Create a window that requests landscape orientation. It will define device orientation
    478         // by default.
    479         final WindowState window = createWindow(null /* parent */, TYPE_BASE_APPLICATION, dc, "w");
    480         window.mAppToken.setOrientation(SCREEN_ORIENTATION_LANDSCAPE);
    481 
    482         final WindowState keyguard = createWindow(null, TYPE_STATUS_BAR, dc, "keyguard");
    483         keyguard.mHasSurface = true;
    484         keyguard.mAttrs.screenOrientation = SCREEN_ORIENTATION_UNSPECIFIED;
    485 
    486         assertEquals("Screen orientation must be defined by the app window by default",
    487                 SCREEN_ORIENTATION_LANDSCAPE, dc.getOrientation());
    488 
    489         keyguard.mAttrs.screenOrientation = SCREEN_ORIENTATION_PORTRAIT;
    490         assertEquals("Visible keyguard must influence device orientation",
    491                 SCREEN_ORIENTATION_PORTRAIT, dc.getOrientation());
    492 
    493         sWm.setKeyguardGoingAway(true);
    494         assertEquals("Keyguard that is going away must not influence device orientation",
    495                 SCREEN_ORIENTATION_LANDSCAPE, dc.getOrientation());
    496     }
    497 
    498     @Test
    499     public void testDisableDisplayInfoOverrideFromWindowManager() {
    500         final DisplayContent dc = createNewDisplay();
    501 
    502         assertTrue(dc.mShouldOverrideDisplayConfiguration);
    503         sWm.dontOverrideDisplayInfo(dc.getDisplayId());
    504 
    505         assertFalse(dc.mShouldOverrideDisplayConfiguration);
    506         verify(sWm.mDisplayManagerInternal, times(1))
    507                 .setDisplayInfoOverrideFromWindowManager(dc.getDisplayId(), null);
    508     }
    509 
    510     private static void verifySizes(DisplayContent displayContent, int expectedBaseWidth,
    511                              int expectedBaseHeight, int expectedBaseDensity) {
    512         assertEquals(displayContent.mBaseDisplayWidth, expectedBaseWidth);
    513         assertEquals(displayContent.mBaseDisplayHeight, expectedBaseHeight);
    514         assertEquals(displayContent.mBaseDisplayDensity, expectedBaseDensity);
    515     }
    516 
    517     private void assertForAllWindowsOrder(List<WindowState> expectedWindowsBottomToTop) {
    518         final LinkedList<WindowState> actualWindows = new LinkedList<>();
    519 
    520         // Test forward traversal.
    521         mDisplayContent.forAllWindows(actualWindows::addLast, false /* traverseTopToBottom */);
    522         assertThat("bottomToTop", actualWindows, is(expectedWindowsBottomToTop));
    523 
    524         actualWindows.clear();
    525 
    526         // Test backward traversal.
    527         mDisplayContent.forAllWindows(actualWindows::addLast, true /* traverseTopToBottom */);
    528         assertThat("topToBottom", actualWindows, is(reverseList(expectedWindowsBottomToTop)));
    529     }
    530 
    531     private static List<WindowState> reverseList(List<WindowState> list) {
    532         final ArrayList<WindowState> result = new ArrayList<>(list);
    533         Collections.reverse(result);
    534         return result;
    535     }
    536 
    537     private MotionEvent createTapEvent(float x, float y, boolean isDownEvent) {
    538         final long downTime = SystemClock.uptimeMillis();
    539         final long eventTime = SystemClock.uptimeMillis() + 100;
    540         final int metaState = 0;
    541 
    542         return MotionEvent.obtain(
    543                 downTime,
    544                 eventTime,
    545                 isDownEvent ? MotionEvent.ACTION_DOWN : MotionEvent.ACTION_UP,
    546                 x,
    547                 y,
    548                 metaState);
    549     }
    550 }
    551