Clear old clip rect when creating new surface.

This fixes an issue where a window state animator holds on to old clip
rect from previous transition and applies it to the newly created surface.

Bug: 22851074
Change-Id: Ic416a2a0c5d0f69fc80d5656541256ade41c9c36

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

@@ -40,7 +40,6 @@ import android.graphics.RectF;
 import android.graphics.Region;
 import android.os.Debug;
 import android.os.RemoteException;
-import android.os.UserHandle;
 import android.util.Slog;
 import android.view.Display;
 import android.view.DisplayInfo;
@@ -837,6 +836,8 @@ class WindowStateAnimator {
             mSurfaceX = 0;
             mSurfaceY = 0;
             w.mLastSystemDecorRect.set(0, 0, 0, 0);
+            mHasClipRect = false;
+            mClipRect.set(0, 0, 0, 0);
             mLastClipRect.set(0, 0, 0, 0);
 
             // Set up surface control with initial size.