Fix fillsParent() always be false on finishing activity

ActivityRecord#occludesParent() returns true only if the activity
is not finish and is opaque since 99d6f0e, which caused side-effects
to ActivityRecord#fillParent().

Bug: 155343623
Test: Close a freeform activity and examine the app transition
Change-Id: I30f7071e5dadade8dc0aa3a7c8a573bf72c81f72

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

@@ -2115,12 +2115,20 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
 
     @Override
     boolean fillsParent() {
-        return occludesParent();
+        return occludesParent(true /* includingFinishing */);
     }
 
-    /** Returns true if this activity is opaque and fills the entire space of this task. */
+    /** Returns true if this activity is not finishing, is opaque and fills the entire space of
+     * this task. */
     boolean occludesParent() {
-        return !finishing && mOccludesParent;
+        return occludesParent(false /* includingFinishing */);
+    }
+
+    private boolean occludesParent(boolean includingFinishing) {
+        if (!includingFinishing && finishing) {
+            return false;
+        }
+        return mOccludesParent;
     }
 
     boolean setOccludesParent(boolean occludesParent) {
@@ -7539,7 +7547,7 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
         if (mThumbnail != null){
             mThumbnail.dumpDebug(proto, THUMBNAIL);
         }
-        proto.write(FILLS_PARENT, mOccludesParent);
+        proto.write(FILLS_PARENT, fillsParent());
         proto.write(APP_STOPPED, mAppStopped);
         proto.write(TRANSLUCENT, !occludesParent());
         proto.write(VISIBLE, mVisible);

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

@@ -295,6 +295,7 @@ class ActivityTestsBase extends SystemServiceTestsBase {
                 // fullscreen value is normally read from resources in ctor, so for testing we need
                 // to set it somewhere else since we can't mock resources.
                 doReturn(true).when(activity).occludesParent();
+                doReturn(true).when(activity).fillsParent();
                 mTask.addChild(activity);
                 // Make visible by default...
                 activity.setVisible(true);