Move context-related callbacks into OutputSurface

cc/delegating_renderer.h

Index: cc/delegating_renderer.h
diff --git a/cc/delegating_renderer.h b/cc/delegating_renderer.h
index d742dcb67f3bc166b1fc530040e986c0de74422a..dea73eea97cdc27f9a5c80c7d0f50ec61cf03d09 100644
--- a/cc/delegating_renderer.h
+++ b/cc/delegating_renderer.h
@@ -16,9 +16,7 @@ class OutputSurface;
 class ResourceProvider;
 
 class CC_EXPORT DelegatingRenderer :
-    public Renderer,
-    public NON_EXPORTED_BASE(
-        WebKit::WebGraphicsContext3D::WebGraphicsContextLostCallback)
+    public Renderer
 {
  public:
   static scoped_ptr<DelegatingRenderer> Create(
@@ -48,9 +46,6 @@ class CC_EXPORT DelegatingRenderer :
                                       size_t bytes_visible_and_nearby,
                                       size_t bytes_allocated) OVERRIDE {}
 
-  // WebGraphicsContext3D::WebGraphicsContextLostCallback implementation.
-  virtual void onContextLost() OVERRIDE;
-
 private:
   DelegatingRenderer(RendererClient* client,
                      OutputSurface* output_surface,