Don't change the zoom filter during the zoom animation.

Call another invalidate() to draw with the final filters.
This fixed the problem where the end of the zoom animation
is slow and jagged.

Fix http://b/issue?id=2126523

core/java/android/webkit/WebView.java

@@ -2763,7 +2763,8 @@ public class WebView extends AbsoluteLayout
                 zoomScale = mZoomScale;
                 // set mZoomScale to be 0 as we have done animation
                 mZoomScale = 0;
-                animateZoom = false;    // inform drawContentPicture we're done
+                // call invalidate() again to draw with the final filters
+                invalidate();
                 if (mNeedToAdjustWebTextView) {
                     mNeedToAdjustWebTextView = false;
                     mWebTextView.setTextSize(TypedValue.COMPLEX_UNIT_PX,