arc-bridge: Introduce the ArcService class

components/arc/ime/arc_ime_ipc_host.h

Index: components/arc/ime/arc_ime_ipc_host.h
diff --git a/components/arc/ime/arc_ime_ipc_host.h b/components/arc/ime/arc_ime_ipc_host.h
index e050e84bd448620f1419aa371225139f20bc3ed5..1d38b57ee4de147b8ddadf62d01dda9f63724925 100644
--- a/components/arc/ime/arc_ime_ipc_host.h
+++ b/components/arc/ime/arc_ime_ipc_host.h
@@ -35,7 +35,7 @@ class ArcImeIpcHost : public ImeHost,
     virtual void OnCursorRectChanged(const gfx::Rect& rect) = 0;
   };
 
-  ArcImeIpcHost(Delegate* delegate, ArcBridgeService* bridge_service);
+  ArcImeIpcHost(Delegate* delegate, ArcBridgeService* arc_bridge_service);
   ~ArcImeIpcHost() override;
 
   // arc::ArcBridgeService::Observer:
@@ -51,9 +51,10 @@ class ArcImeIpcHost : public ImeHost,
   void OnCursorRectChanged(arc::CursorRectPtr rect) override;
 
  private:
+  ArcBridgeService* const arc_bridge_service_;  // owned by ArcServiceManager.
+
   mojo::Binding<ImeHost> binding_;
   Delegate* const delegate_;
-  ArcBridgeService* const bridge_service_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcImeIpcHost);
 };