arc-bridge: Start ArcBridgeService on session start

chrome/browser/chromeos/chrome_browser_main_chromeos.h

Index: chrome/browser/chromeos/chrome_browser_main_chromeos.h
diff --git a/chrome/browser/chromeos/chrome_browser_main_chromeos.h b/chrome/browser/chromeos/chrome_browser_main_chromeos.h
index 8e64753c5c779fcb5121e896aaebbb492f83a51e..0b546411c6fa438dd9a006fbae8dd1c3085c4182 100644
--- a/chrome/browser/chromeos/chrome_browser_main_chromeos.h
+++ b/chrome/browser/chromeos/chrome_browser_main_chromeos.h
@@ -15,6 +15,10 @@ namespace session_manager {
 class SessionManager;
 }
 
+namespace arc {
+class ArcBridgeService;
+}
+
 namespace chromeos {
 
 class DataPromoNotification;
@@ -77,6 +81,8 @@ class ChromeBrowserMainPartsChromeos : public ChromeBrowserMainPartsLinux {
 
   scoped_refptr<chromeos::ExternalMetrics> external_metrics_;
 
+  scoped_ptr<arc::ArcBridgeService> arc_bridge_service_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainPartsChromeos);
 };