Delete paint invalidation rect tracking.

sky/engine/web/WebViewImpl.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 59 matching lines @@
     // WebWidget methods:
     virtual void close() override;
     virtual WebSize size() override;
 
     virtual void resize(const WebSize&) override;
 
     virtual void beginFrame(const WebBeginFrameArgs&) override;
 
     virtual void layout() override;
     virtual void paint(WebCanvas*, const WebRect&) override;
-    virtual bool isTrackingRepaints() const override;
     virtual bool handleInputEvent(const WebInputEvent&) override;
     virtual void setCursorVisibilityState(bool isVisible) override;
     virtual void mouseCaptureLost() override;
     virtual void setFocus(bool enable) override;
     virtual bool setComposition(
         const WebString& text,
         const WebVector<WebCompositionUnderline>& underlines,
         int selectionStart,
         int selectionEnd) override;
     virtual bool confirmComposition() override;
@@ skipping 259 matching lines @@
     bool m_userGestureObserved;
 };
 
 // We have no ways to check if the specified WebView is an instance of
 // WebViewImpl because WebViewImpl is the only implementation of WebView.
 DEFINE_TYPE_CASTS(WebViewImpl, WebView, webView, true, true);
 
 } // namespace blink
 
 #endif  // SKY_ENGINE_WEB_WEBVIEWIMPL_H_