Force a WebView pictureset invalidation on screen rotation.

This fixes some stale content issues when rotating the screen.

Bug: 5357237
Change-Id: Ib41a659ec99419cdf94ad5321c224a33b1f21359

core/java/android/webkit/WebView.java

@@ -4300,6 +4300,7 @@ public class WebView extends AbsoluteLayout
             selectionDone();
         }
         mOrientation = newConfig.orientation;
+        contentInvalidateAll();
     }
 
     /**