Clear page display after navigation if no rendered output arrives

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 065ffcff170b05d340fd08bdb8a1e3f6749fb6e6..f01d3c24c598d1f1271c67982743bd7d90d0260b 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.h
+++ b/content/browser/renderer_host/render_widget_host_view_base.h
@@ -164,6 +164,8 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
   virtual void OnSwapCompositorFrame(uint32 output_surface_id,
                                      scoped_ptr<cc::CompositorFrame> frame) {}
 
+  virtual void ClearCompositorFrame() {}

[Charlie Reis, 2015/09/14 20:54:55]

Should this ever be left unimplemented, or should we make it pure virtual? 
Seems like it's a potential security issue to have some RHWVs that leave it as a
no-op.

[kenrb, 2015/09/14 21:29:36]

RenderWidgetHostViewChildFrame and RenderWidgetHostViewGuest do not implement
it, because the URL of their content is not displayed in the omnibar.

[Charlie Reis, 2015/09/14 21:40:18]

One option would be to put an empty implementation in
RenderWidgetHostViewChildFrame (inherited by RWHVG) but still leave it pure
virtual here, so that future platform subclasses have to implement it.  In the
future, it seems more likely that we'll add more platform subclasses than more
"subframe" subclasses.

I think that might be worthwhile, but I'll defer to you if there's a reason not
to.

[kenrb, 2015/09/15 15:25:41]

This makes sense. I've made the change.

+
   // Because the associated remote WebKit instance can asynchronously
   // prevent-default on a dispatched touch event, the touch events are queued in
   // the GestureRecognizer until invocation of ProcessAckedTouchEvent releases