Ensure RemoteViewportIntersection rect persists across frame navigations

content/browser/frame_host/render_widget_host_view_child_frame.cc

 // 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.
 
 #include "content/browser/frame_host/render_widget_host_view_child_frame.h"
 
 #include <algorithm>
 #include <utility>
 #include <vector>
 
@@ skipping 596 matching lines @@
 
   return frame_connector_->TransformPointToCoordSpaceForView(
       point, target_view, cc::SurfaceId(frame_sink_id_, local_surface_id_),
       transformed_point);
 }
 
 bool RenderWidgetHostViewChildFrame::IsRenderWidgetHostViewChildFrame() {
   return true;
 }
 
+void RenderWidgetHostViewChildFrame::WillSendScreenRects() {
+  if (frame_connector_)
+    UpdateViewportIntersection(frame_connector_->viewport_intersection());
+}
+
 #if defined(OS_MACOSX)
 ui::AcceleratedWidgetMac*
 RenderWidgetHostViewChildFrame::GetAcceleratedWidgetMac() const {
   return nullptr;
 }
 
 void RenderWidgetHostViewChildFrame::SetActive(bool active) {
 }
 
 void RenderWidgetHostViewChildFrame::ShowDefinitionForSelection() {
@@ skipping 190 matching lines @@
     auto origin = GetViewBounds().origin() -
                   frame_connector_->GetRootRenderWidgetHostView()
                       ->GetViewBounds()
                       .origin();
     return gfx::Point(origin.x(), origin.y());
   }
   return gfx::Point();
 }
 
 }  // namespace content