Add ArcAuthService to handle IPC request from ARC

components/arc/auth/arc_auth_service.h

Index: components/arc/auth/arc_auth_service.h
diff --git a/components/arc/auth/arc_auth_service.h b/components/arc/auth/arc_auth_service.h
new file mode 100644
index 0000000000000000000000000000000000000000..d26288e7e5a447676eabdcca63ea799deda416d8
--- /dev/null
+++ b/components/arc/auth/arc_auth_service.h
@@ -0,0 +1,20 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_ARC_AUTH_ARC_AUTH_SERVICE_H_
+#define COMPONENTS_ARC_AUTH_ARC_AUTH_SERVICE_H_
+
+namespace arc {
+
+class ArcAuthService {
+ public:
+  virtual ~ArcAuthService() {}
+
+  // Starts listening to state changes of the ArcBridgeService.
+  virtual void StartObservingBridgeServiceChanges() = 0;
+};
+
+}  // namespace arc
+
+#endif  // COMPONENTS_ARC_AUTH_ARC_AUTH_SERVICE_H_