Workaround issue of getting 0,0,0,0 inval rects

 Bug: 6142700
 WebKit is sending an empty inval rect for some reason, which results
 in WebView not being invalidated. Assume an empty inval means a
 full inval

Change-Id: Ib93b806f8f8fd2039e2a0e43de2372c3e6be2433

Author: jreck

core/java/android/webkit/WebViewClassic.java

@@ -8679,7 +8679,12 @@ void setNewPicture(final WebViewCore.DrawData draw, boolean updateBaseLayer) {
             Log.v(LOGTAG, "NEW_PICTURE_MSG_ID {" +
                     b.left+","+b.top+","+b.right+","+b.bottom+"}");
         }
-        invalidateContentRect(draw.mInvalRegion.getBounds());
+        Rect invalBounds = draw.mInvalRegion.getBounds();
+        if (!invalBounds.isEmpty()) {
+            invalidateContentRect(invalBounds);
+        } else {
+            mWebView.invalidate();
+        }
 
         if (mPictureListener != null) {
             mPictureListener.onNewPicture(getWebView(), capturePicture());