Hook up CryptAuthGCMManager to the enrollment and device sync managers.

components/proximity_auth/webui/proximity_auth_ui_delegate.h

Index: components/proximity_auth/webui/proximity_auth_ui_delegate.h
diff --git a/components/proximity_auth/webui/proximity_auth_ui_delegate.h b/components/proximity_auth/webui/proximity_auth_ui_delegate.h
index 6de61e790f5c48041d7dc8e3261c4b5057d6c6b9..bbb3787d2444968d8aba0d1d2f7256b808cae2c3 100644
--- a/components/proximity_auth/webui/proximity_auth_ui_delegate.h
+++ b/components/proximity_auth/webui/proximity_auth_ui_delegate.h
@@ -10,6 +10,10 @@
 
 class PrefService;
 
+namespace gcm {
+class GCMDriver;
+}
+
 namespace proximity_auth {
 
 class CryptAuthClientFactory;
@@ -33,6 +37,9 @@ class ProximityAuthUIDelegate {
   // Constructs the DeviceClassifier message that is sent to CryptAuth for all
   // API requests.
   virtual cryptauth::DeviceClassifier GetDeviceClassifier() = 0;
+
+  // Returns the GCMDriver instance used by Chrome.
+  virtual gcm::GCMDriver* GetGCMDriver() = 0;
 };
 
 }  // namespace proximity_auth