[android] Resize the android_webview if it's 0x0 initially.

android_webview/browser/renderer_host/view_renderer_host.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ANDROID_WEBVIEW_BROWSER_RENDER_HOST_VIEW_RENDERER_HOST_H_
 #define ANDROID_WEBVIEW_BROWSER_RENDER_HOST_VIEW_RENDERER_HOST_H_
 
 #include "base/threading/non_thread_safe.h"
 #include "content/public/browser/web_contents_observer.h"
 
 namespace android_webview {
 
 // Provides RenderViewHost wrapper functionality for sending WebView-specific
 // IPC messages to the renderer and from there to WebKit.
 class ViewRendererHost : public content::WebContentsObserver,
                          public base::NonThreadSafe {
  public:
   class Client {
    public:
     virtual void OnPictureUpdated(int process_id, int render_view_id) = 0;
+    virtual void OnPageScaleFactorChanged(int process_id,
+                                          int render_view_id,
+                                          float page_scale_factor) = 0;
 
    protected:
     virtual ~Client() {}
   };
 
   ViewRendererHost(content::WebContents* contents, Client* client);
   virtual ~ViewRendererHost();
 
   // Captures the latest available picture pile synchronously.
   void CapturePictureSync();
 
   // Enables updating picture piles on every new frame.
   // OnPictureUpdated is called when a new picture is available,
   // stored by renderer id in RendererPictureMap.
   void EnableCapturePictureCallback(bool enabled);
 
   using content::WebContentsObserver::Observe;
 
  private:
   // content::WebContentsObserver implementation.
   virtual void RenderViewGone(base::TerminationStatus status) OVERRIDE;
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
   void OnPictureUpdated();
   void OnDidActivateAcceleratedCompositing(int input_handler_id);
+  void OnPageScaleFactorChanged(float page_scale_factor);
 
   bool IsRenderViewReady() const;
 
   Client* client_;
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_RENDER_HOST_VIEW_RENDERER_HOST_H_