Override the fillsParent() on TaskFragment

The default implementation of fillsParent() on TaskFragment which
results in the system can not get the specified orientation from the
activity in TaskFragment when traversing the windowContainers with
getOrientation().

Move the implementation of fillsParent() from Task to TaskFragment.
Report the taskFragment fills the parent in a full screen window
or matches the parents' bounds. So, we can get the orientation from
activity successfully.

Bug: 207605841
Test: Launch wallpaper picker and check the orientation when rotate
Change-Id: Ieb7e7e009fcfb337b2c7def1b892831d09d98951

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

@@ -3140,14 +3140,6 @@ class Task extends TaskFragment {
                 || activityType == ACTIVITY_TYPE_ASSISTANT;
     }
 
-    @Override
-    boolean fillsParent() {
-        // From the perspective of policy, we still want to report that this task fills parent
-        // in fullscreen windowing mode even it doesn't match parent bounds because there will be
-        // letterbox around its real content.
-        return getWindowingMode() == WINDOWING_MODE_FULLSCREEN || matchParentBounds();
-    }
-
     @Override
     void forAllLeafTasks(Consumer<Task> callback, boolean traverseTopToBottom) {
         final int count = mChildren.size();

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

@@ -2346,6 +2346,14 @@ class TaskFragment extends WindowContainer<WindowContainer> {
         return true;
     }
 
+    @Override
+    boolean fillsParent() {
+        // From the perspective of policy, we still want to report that this task fills parent
+        // in fullscreen windowing mode even it doesn't match parent bounds because there will be
+        // letterbox around its real content.
+        return getWindowingMode() == WINDOWING_MODE_FULLSCREEN || matchParentBounds();
+    }
+
     boolean dump(String prefix, FileDescriptor fd, PrintWriter pw, boolean dumpAll,
             boolean dumpClient, String dumpPackage, final boolean needSep, Runnable header) {
         boolean printed = false;