Clean up AnimationThread default handler

To avoid flakiness during unit tests. Note that this is a different
object than WindowManagerService.mAnimationHandler.

Bug: N/A
Test: Let them pass!
Change-Id: I71a775b0599facb4172c86b28d7a9f7e36c65673

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

@@ -40,6 +40,10 @@ class SystemServiceTestsBase {
         mLockRule.waitForLocked(mSystemServicesTestRule::waitUntilWindowManagerHandlersIdle);
     }
 
+    void cleanupWindowManagerHandlers() {
+        mLockRule.waitForLocked(mSystemServicesTestRule::cleanupWindowManagerHandlers);
+    }
+
     boolean waitHandlerIdle(Handler handler) {
         return waitHandlerIdle(handler, 0 /* timeout */);
     }

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

@@ -355,6 +355,8 @@ public class SystemServicesTestRule implements TestRule {
         }
         wm.mH.removeCallbacksAndMessages(null);
         wm.mAnimationHandler.removeCallbacksAndMessages(null);
+        // This is a different handler object than the wm.mAnimationHandler above.
+        AnimationThread.getHandler().removeCallbacksAndMessages(null);
         SurfaceAnimationThread.getHandler().removeCallbacksAndMessages(null);
     }
 
@@ -367,6 +369,8 @@ public class SystemServicesTestRule implements TestRule {
         wm.mH.removeMessages(WindowManagerService.H.FORCE_GC);
         waitHandlerIdle(wm.mH);
         waitHandlerIdle(wm.mAnimationHandler);
+        // This is a different handler object than the wm.mAnimationHandler above.
+        waitHandlerIdle(AnimationThread.getHandler());
         waitHandlerIdle(SurfaceAnimationThread.getHandler());
     }
 

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

@@ -175,7 +175,7 @@ class WindowTestsBase extends SystemServiceTestsBase {
             }
 
             // Cleaned up everything in Handler.
-            mSystemServicesTestRule.cleanupWindowManagerHandlers();
+            cleanupWindowManagerHandlers();
         } catch (Exception e) {
             Log.e(TAG, "Failed to tear down test", e);
             throw e;