Ensure RemoteViewportIntersection rect persists across frame navigations

content/browser/renderer_host/render_widget_host_view_base.h

Index: content/browser/renderer_host/render_widget_host_view_base.h
diff --git a/content/browser/renderer_host/render_widget_host_view_base.h b/content/browser/renderer_host/render_widget_host_view_base.h
index 1f1a6b919a3e29df619bfcc1974f485021d861da..5ccd2226d58b3961a0a14652de63fd25c71e3886 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.h
+++ b/content/browser/renderer_host/render_widget_host_view_base.h
@@ -317,6 +317,10 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   // need to also be resolved.
   virtual bool IsRenderWidgetHostViewChildFrame();
 
+  // Notify the View that a screen rect update is being sent to the
+  // RenderWidget. Related platform-specific updates can be sent from here.
+  virtual void OnSendScreenRects() {}

[ncarter (slow), 2017/05/30 17:51:09]

Optional: "WillSendScreenRects" would be my pick to name this method. To me at
least, "OnX" connotes having gotten a legacy IPC message named X, though there
are certainly already a bunch of methods in this class (OnSurfaceChanged) that
don't follow that pattern -- so I am ok sticking with the On name if we want to
be consistent with those.

[kenrb, 2017/05/30 18:25:10]

That makes sense. Done.

+
   // Returns true if the current view is in virtual reality mode.
   virtual bool IsInVR() const;