Add ArcAuthService to handle IPC request from ARC

components/arc/arc_bridge_service.h

Index: components/arc/arc_bridge_service.h
diff --git a/components/arc/arc_bridge_service.h b/components/arc/arc_bridge_service.h
index 12aae9d30f76d063bda8a67dfb05e6add5973802..e1433c339aa8d516ac3e4aece8acdce53806d75a 100644
--- a/components/arc/arc_bridge_service.h
+++ b/components/arc/arc_bridge_service.h
@@ -76,6 +76,9 @@ class ArcBridgeService : public ArcBridgeHost {
     // Called whenever the ARC app list is ready.
     virtual void OnAppInstanceReady() {}
 
+    // Called whenever the ARC auth is ready.
+    virtual void OnAuthInstanceReady() {}
+
     // Called whenever the ARC input is ready.
     virtual void OnInputInstanceReady() {}
 
@@ -142,6 +145,7 @@ class ArcBridgeService : public ArcBridgeHost {
   // you want to be notified when this is ready. This can only be called on the
   // thread that this class was created on.
   AppInstance* app_instance() { return app_ptr_.get(); }
+  AuthInstance* auth_instance() { return auth_ptr_.get(); }
   InputInstance* input_instance() { return input_ptr_.get(); }
   NotificationsInstance* notifications_instance() {
     return notifications_ptr_.get();
@@ -152,6 +156,7 @@ class ArcBridgeService : public ArcBridgeHost {
 
   // ArcHost:
   void OnAppInstanceReady(AppInstancePtr app_ptr) override;
+  void OnAuthInstanceReady(AuthInstancePtr auth_ptr) override;
   void OnInputInstanceReady(InputInstancePtr input_ptr) override;
   void OnNotificationsInstanceReady(
       NotificationsInstancePtr notifications_ptr) override;
@@ -186,6 +191,7 @@ class ArcBridgeService : public ArcBridgeHost {
 
   // Mojo interfaces.
   AppInstancePtr app_ptr_;
+  AuthInstancePtr auth_ptr_;
   InputInstancePtr input_ptr_;
   NotificationsInstancePtr notifications_ptr_;
   PowerInstancePtr power_ptr_;