arc: Rename methods in ArcSessionManager::Observer.

chrome/browser/chromeos/arc/arc_session_manager.h

Index: chrome/browser/chromeos/arc/arc_session_manager.h
diff --git a/chrome/browser/chromeos/arc/arc_session_manager.h b/chrome/browser/chromeos/arc/arc_session_manager.h
index 5c6a16e759de31556166ac3b5dbf846a999b6347..3355bbb3a0f587941bef5211d919df1bb221f9fd 100644
--- a/chrome/browser/chromeos/arc/arc_session_manager.h
+++ b/chrome/browser/chromeos/arc/arc_session_manager.h
@@ -103,13 +103,13 @@ class ArcSessionManager : public ArcService,
     virtual ~Observer() = default;
 
     // Called to notify that ARC bridge is shut down.
-    virtual void OnShutdownBridge() {}
+    virtual void OnArcBridgeShutdown() {}
 
     // Called to notify that ARC enabled state has been updated.
-    virtual void OnOptInEnabled(bool enabled) {}
+    virtual void OnArcOptInChanged(bool enabled) {}
 
     // Called to notify that ARC has been initialized successfully.
-    virtual void OnInitialStart() {}
+    virtual void OnArcInitialStart() {}
 
     // Called to notify that Android data has been removed. Used in
     // browser_tests