Restrict CM API interface request and message dispatch.

content/public/browser/content_browser_client.h

Index: content/public/browser/content_browser_client.h
diff --git a/content/public/browser/content_browser_client.h b/content/public/browser/content_browser_client.h
index 571f9937a8fea459440b36d9bed1576e880e0d55..122447daa2936c90dad158829e83f54ea58ff129 100644
--- a/content/public/browser/content_browser_client.h
+++ b/content/public/browser/content_browser_client.h
@@ -67,6 +67,10 @@ class AudioManager;
 class CdmFactory;
 }
 
+namespace mojo {
+class ScopedInterfaceEndpointHandle;
+}
+
 namespace service_manager {
 class Service;
 struct BindSourceInfo;
@@ -656,6 +660,14 @@ class CONTENT_EXPORT ContentBrowserClient {
       const std::string& interface_name,
       mojo::ScopedMessagePipeHandle interface_pipe) {}
 
+  // Content was unable to bind a request for this associated interface, so the
+  // embedder should try. Returns true if the |handle| was actually taken and
+  // bound; false otherwise.
+  virtual bool BindAssociatedInterfaceRequestFromFrame(
+      RenderFrameHost* render_frame_host,
+      const std::string& interface_name,
+      mojo::ScopedInterfaceEndpointHandle* handle);
+
   // (Currently called only from GPUProcessHost, move somewhere more central).
   // Called when a request to bind |interface_name| on |interface_pipe| is
   // received from |source_info.identity|. If the request is bound,