mus: Fix showing guest views in --mash and --mus.

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 40b1161024268c40bfc1b12155e0776e0da8a06a..54bf4ab10c83239f7cedbfb363e58084fe704e3e 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.h
+++ b/content/browser/renderer_host/render_widget_host_view_base.h
@@ -46,6 +46,7 @@ struct ViewHostMsg_SelectionBounds_Params;
 
 namespace cc {
 struct BeginFrameAck;
+class SurfaceInfo;
 }  // namespace cc
 
 namespace media {
@@ -227,6 +228,7 @@ class CONTENT_EXPORT RenderWidgetHostViewBase : public RenderWidgetHostView,
                                      cc::CompositorFrame frame) = 0;
 
   virtual void OnBeginFrameDidNotSwap(const cc::BeginFrameAck& ack) {}
+  virtual void OnSurfaceChanged(const cc::SurfaceInfo& surface_info) {}
 
   // This method exists to allow removing of displayed graphics, after a new
   // page has been loaded, to prevent the displayed URL from being out of sync