Introduce the Blink NotificationService, move permission checks there

content/renderer/mojo/blink_service_registry_impl.h

Index: content/renderer/mojo/blink_service_registry_impl.h
diff --git a/content/renderer/mojo/blink_service_registry_impl.h b/content/renderer/mojo/blink_service_registry_impl.h
index 8bd86321e68d722c3f5cdf53fc739cb9f6ed9362..b731e9512c489180f6c3e94f39b850c507d2a43e 100644
--- a/content/renderer/mojo/blink_service_registry_impl.h
+++ b/content/renderer/mojo/blink_service_registry_impl.h
@@ -6,10 +6,15 @@
 #define CONTENT_RENDERER_MOJO_BLINK_SERVICE_REGISTRY_IMPL_H_
 
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "mojo/public/cpp/system/message_pipe.h"
 #include "third_party/WebKit/public/platform/ServiceRegistry.h"
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace content {
 
 class ServiceRegistry;
@@ -29,6 +34,10 @@ class BlinkServiceRegistryImpl : public blink::ServiceRegistry {
  private:
   const base::WeakPtr<content::ServiceRegistry> service_registry_;
 
+  scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
+
+  base::WeakPtrFactory<BlinkServiceRegistryImpl> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(BlinkServiceRegistryImpl);
 };