Add embedder api for participating in gpu logic

content/public/app/content_main_delegate.h

Index: content/public/app/content_main_delegate.h
diff --git a/content/public/app/content_main_delegate.h b/content/public/app/content_main_delegate.h
index 6bd725d0f5ce7481203e959707c7d0555af0951b..7fecaea2b480ff63fd4c940b4fdb95cf9e938363 100644
--- a/content/public/app/content_main_delegate.h
+++ b/content/public/app/content_main_delegate.h
@@ -16,6 +16,7 @@ class ScopedVector;
 namespace content {
 
 class ContentBrowserClient;
+class ContentGpuClient;
 class ContentPluginClient;
 class ContentRendererClient;
 class ContentUtilityClient;
@@ -88,6 +89,7 @@ class CONTENT_EXPORT ContentMainDelegate {
   // content. If an embedder wants the default (empty) implementation, don't
   // override this.
   virtual ContentBrowserClient* CreateContentBrowserClient();
+  virtual ContentGpuClient* CreateContentGpuClient();
   virtual ContentPluginClient* CreateContentPluginClient();
   virtual ContentRendererClient* CreateContentRendererClient();
   virtual ContentUtilityClient* CreateContentUtilityClient();