Remove canStartRecentsAnimation logics

Since we won't cancel recent animation during task switching as we
still keeps the connection to reparent the new task animation target
with onTaskAppeared, so we don't need to care about the next recents
animation starts timing if the next task transition is set.

Bug: 152480470
Test: swipe to next task, see if any flickring when swipped.
Change-Id: I5abfbefa9b05751b08c2b235609270977ae55292

services/core/java/com/android/server/wm/RecentsAnimation.java

@@ -165,17 +165,6 @@ class RecentsAnimation implements RecentsAnimationCallbacks,
         ProtoLog.d(WM_DEBUG_RECENTS_ANIMATIONS, "startRecentsActivity(): intent=%s", mTargetIntent);
         Trace.traceBegin(TRACE_TAG_WINDOW_MANAGER, "RecentsAnimation#startRecentsActivity");
 
-        // TODO(multi-display) currently only support recents animation in default display.
-        final DisplayContent dc =
-                mService.mRootWindowContainer.getDefaultDisplay().mDisplayContent;
-        if (!mWindowManager.canStartRecentsAnimation()) {
-            notifyAnimationCancelBeforeStart(recentsAnimationRunner);
-            ProtoLog.d(WM_DEBUG_RECENTS_ANIMATIONS,
-                    "Can't start recents animation, nextAppTransition=%s",
-                        dc.mAppTransition.getAppTransition());
-            return;
-        }
-
         // If the activity is associated with the recents stack, then try and get that first
         ActivityStack targetStack = mDefaultTaskDisplayArea.getStack(WINDOWING_MODE_UNDEFINED,
                 mTargetActivityType);

services/core/java/com/android/server/wm/WindowManagerService.java

@@ -2755,18 +2755,6 @@ public class WindowManagerService extends IWindowManager.Stub
         return mRecentsAnimationController;
     }
 
-    /**
-     * @return Whether the next recents animation can continue to start. Called from
-     *         {@link RecentsAnimation#startRecentsActivity}.
-     */
-    boolean canStartRecentsAnimation() {
-        // TODO(multi-display): currently only default display support recent activity
-        if (getDefaultDisplayContentLocked().mAppTransition.isTransitionSet()) {
-            return false;
-        }
-        return true;
-    }
-
     void cancelRecentsAnimation(
             @RecentsAnimationController.ReorderMode int reorderMode, String reason) {
         if (mRecentsAnimationController != null) {

services/tests/wmtests/src/com/android/server/wm/RecentsAnimationTest.java

@@ -79,7 +79,6 @@ public class RecentsAnimationTest extends ActivityTestsBase {
         mService.mWindowManager.setRecentsAnimationController(mRecentsAnimationController);
         doNothing().when(mService.mWindowManager).initializeRecentsAnimation(
                 anyInt(), any(), any(), anyInt(), any(), any());
-        doReturn(true).when(mService.mWindowManager).canStartRecentsAnimation();
 
         final RecentTasks recentTasks = mService.getRecentTasks();
         spyOn(recentTasks);