Ensure RemoteViewportIntersection rect persists across frame navigations

content/browser/frame_host/cross_process_frame_connector.h

 // Copyright 2014 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 CONTENT_BROWSER_FRAME_HOST_CROSS_PROCESS_FRAME_CONNECTOR_H_
 #define CONTENT_BROWSER_FRAME_HOST_CROSS_PROCESS_FRAME_CONNECTOR_H_
 
 #include <stdint.h>
 
 #include "cc/output/compositor_frame.h"
@@ skipping 115 matching lines @@
 
   // Unlocks the mouse if the mouse is locked.
   void UnlockMouse();
 
   // Returns the parent RenderWidgetHostView or nullptr it it doesn't have one.
   virtual RenderWidgetHostViewBase* GetParentRenderWidgetHostView();
 
   // Returns the view for the top-level frame under the same WebContents.
   RenderWidgetHostViewBase* GetRootRenderWidgetHostView();
 
+  gfx::Rect viewport_intersection() const {

[dcheng, 2017/05/30 19:54:11]

Nit: consider returning a const ref to avoid a copy

[kenrb, 2017/05/30 21:19:20]

Done.

+    return viewport_intersection_rect_;
+  }
+
   // Exposed for tests.
   RenderWidgetHostViewBase* GetRootRenderWidgetHostViewForTesting() {
     return GetRootRenderWidgetHostView();
   }
 
  private:
+  friend class MockCrossProcessFrameConnector;
+
   // Handlers for messages received from the parent frame.
   void OnFrameRectChanged(const gfx::Rect& frame_rect);
   void OnUpdateViewportIntersection(const gfx::Rect& viewport_intersection);
   void OnVisibilityChanged(bool visible);
   void OnSatisfySequence(const cc::SurfaceSequence& sequence);
   void OnRequireSequence(const cc::SurfaceId& id,
                          const cc::SurfaceSequence& sequence);
 
   void SetRect(const gfx::Rect& frame_rect);
 
   // The RenderFrameProxyHost that routes messages to the parent frame's
   // renderer process.
   RenderFrameProxyHost* frame_proxy_in_parent_renderer_;
 
   // The RenderWidgetHostView for the frame. Initially NULL.
   RenderWidgetHostViewChildFrame* view_;
 
   gfx::Rect child_frame_rect_;
+  gfx::Rect viewport_intersection_rect_;
 
   bool is_scroll_bubbling_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_CROSS_PROCESS_FRAME_CONNECTOR_H_