Resize all changed windows and fix moveTaskToStack

- Add all changing windows to mResizingWindows when an ActivityStack
is resized.

- Stop calling TaskStack.setBounds if the bounds haven't changed.

- Make moving a task from one stack to another work properly.

- Eliminate unused methods and redundant variables in WindowState and
WindowStateAnimator.

Change-Id: I3a950c777bcc50cdeced150d44423d4d0b38af4a
diff --git a/services/java/com/android/server/wm/DisplayContent.java b/services/java/com/android/server/wm/DisplayContent.java
index af7db96..0dbcfb8 100644
--- a/services/java/com/android/server/wm/DisplayContent.java
+++ b/services/java/com/android/server/wm/DisplayContent.java
@@ -309,10 +309,12 @@
      * Propagate the new bounds to all child stack boxes, applying weights as we move down.
      * @param contentRect The bounds to apply at the top level.
      */
-    void setStackBoxSize(Rect contentRect) {
+    boolean setStackBoxSize(Rect contentRect) {
+        boolean change = false;
         for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            mStackBoxes.get(stackBoxNdx).setStackBoxSizes(contentRect);
+            change |= mStackBoxes.get(stackBoxNdx).setStackBoxSizes(contentRect);
         }
+        return change;
     }
 
     Rect getStackBounds(int stackId) {