Let System UI show on external displays (1/3)

Let each display have one status bar and one navigation bar. This is
so on each display, status bar and navigation bar can be laid out with
apps and produce proper insets.

Bug: 117474929
Test: atest com.android.server.wm
Test: Watch YouTube video in fullscreen mode, and see if status bar
      and navigation will be hidden as expected. Swipe on the edge
      of screen and see if status bar and navigation bar are both
      shown as expected.

Change-Id: I1550659b7cd1dd1676bf04483c5b68376ef42905
diff --git a/services/core/java/com/android/server/wm/AppTransitionController.java b/services/core/java/com/android/server/wm/AppTransitionController.java
index e65f3b4..32a6f74 100644
--- a/services/core/java/com/android/server/wm/AppTransitionController.java
+++ b/services/core/java/com/android/server/wm/AppTransitionController.java
@@ -96,14 +96,15 @@
         Trace.traceBegin(Trace.TRACE_TAG_WINDOW_MANAGER, "AppTransitionReady");
 
         if (DEBUG_APP_TRANSITIONS) Slog.v(TAG, "**** GOOD TO GO");
-        int transit = mDisplayContent.mAppTransition.getAppTransition();
+        final AppTransition appTransition = mDisplayContent.mAppTransition;
+        int transit = appTransition.getAppTransition();
         if (mDisplayContent.mSkipAppTransitionAnimation && !isKeyguardGoingAwayTransit(transit)) {
             transit = WindowManager.TRANSIT_UNSET;
         }
         mDisplayContent.mSkipAppTransitionAnimation = false;
         mDisplayContent.mNoAnimationNotifyOnTransitionFinished.clear();
 
-        mDisplayContent.mAppTransition.removeAppTransitionTimeoutCallbacks();
+        appTransition.removeAppTransitionTimeoutCallbacks();
 
         mDisplayContent.mWallpaperMayChange = false;
 
@@ -141,7 +142,7 @@
         // done behind a dream window.
         final ArraySet<Integer> activityTypes = collectActivityTypes(mDisplayContent.mOpeningApps,
                 mDisplayContent.mClosingApps);
-        final boolean allowAnimations = mService.mPolicy.allowAppAnimationsLw();
+        final boolean allowAnimations = mDisplayContent.getDisplayPolicy().allowAppAnimationsLw();
         final AppWindowToken animLpToken = allowAnimations
                 ? findAnimLayoutParamsToken(transit, activityTypes)
                 : null;
@@ -165,15 +166,15 @@
             handleClosingApps(transit, animLp, voiceInteraction);
             handleOpeningApps(transit, animLp, voiceInteraction);
 
-            mDisplayContent.mAppTransition.setLastAppTransition(transit, topOpeningApp,
+            appTransition.setLastAppTransition(transit, topOpeningApp,
                     topClosingApp);
 
-            final int flags = mDisplayContent.mAppTransition.getTransitFlags();
-            layoutRedo = mDisplayContent.mAppTransition.goodToGo(transit, topOpeningApp,
+            final int flags = appTransition.getTransitFlags();
+            layoutRedo = appTransition.goodToGo(transit, topOpeningApp,
                     topClosingApp, mDisplayContent.mOpeningApps, mDisplayContent.mClosingApps);
             handleNonAppWindowsInTransition(transit, flags);
-            mDisplayContent.mAppTransition.postAnimationCallback();
-            mDisplayContent.mAppTransition.clear();
+            appTransition.postAnimationCallback();
+            appTransition.clear();
         } finally {
             mService.mSurfaceAnimationRunner.continueStartingAnimations();
         }
@@ -254,8 +255,8 @@
     }
 
     /**
-     * @return The set of {@link WindowConfiguration.ActivityType}s contained in the set of apps in
-     *         {@code array1} and {@code array2}.
+     * @return The set of {@link android.app.WindowConfiguration.ActivityType}s contained in the set
+     *         of apps in {@code array1} and {@code array2}.
      */
     private static ArraySet<Integer> collectActivityTypes(ArraySet<AppWindowToken> array1,
             ArraySet<AppWindowToken> array2) {