Each displays can have individual app transition.

Include below refectoring items to support per display AppTransition:

WMS / AM refectoring parts:
- Move AppTransition related stuff from WMS into DisplayContent.
- Move WMS.prepareAppTransition into DisplayWindowController.
- Move WMS.executeAppTransition to DisplayWindowController.
- Move ATM.isNextTransitionForward to DisplayWindowController.
- Move WMS.getPendingAppTransition to DisplayWindowController.
- Move WMS.overrideAppTransition like APIs to DisplayWindowController.
- Move ActivityRecord.applyOptionsLocked to AppContainerController.
- Support tracing all display's AppTransition status for
  DisplayContent.pendingLayoutChanges & window hierachy update.
- Modify logics for AppTransition related caller parts.
- Move WindowSurfacePlacer.handleAppTransitionReadyLocked related
  stuffs into added class AppTransitionController.

WM unit test parts:
- Add test case for verifying app transition state per display:
  - AppTransitionTests.testAppTransitionStateForMultiDisplay
  - AppTransitionTests.testCleanAppTransitionWhenTaskStackReparent
- Rename WindowSurfacePlacerTest to AppTransitionControllerTest since
  the test is related handle AppTransition flow.

Bug: 111362605
Test: go/wm-smoke
Test: atest ActivityManagerTransitionSelectionTests
Test: atest ActivityManagerMultiDisplayTests
Test: atest FrameworksServicesTests for DisplayContent / AppTransition
      related tests.
Change-Id: Ic1793aa794eb161bec31fda57847a6ba2ff4f84f
diff --git a/services/tests/servicestests/src/com/android/server/wm/TaskStackTests.java b/services/tests/servicestests/src/com/android/server/wm/TaskStackTests.java
index 53a1185..cb5c1cd 100644
--- a/services/tests/servicestests/src/com/android/server/wm/TaskStackTests.java
+++ b/services/tests/servicestests/src/com/android/server/wm/TaskStackTests.java
@@ -74,7 +74,7 @@
         appWindowToken2.setOrientation(SCREEN_ORIENTATION_PORTRAIT);
 
         assertEquals(SCREEN_ORIENTATION_PORTRAIT, stack.getOrientation());
-        sWm.mClosingApps.add(appWindowToken2);
+        mDisplayContent.mClosingApps.add(appWindowToken2);
         assertEquals(SCREEN_ORIENTATION_LANDSCAPE, stack.getOrientation());
     }