ObserverList::HasObserver now takes a const pointer.

chromeos/dbus/session_manager_client.h

 // Copyright (c) 2012 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 CHROMEOS_DBUS_SESSION_MANAGER_CLIENT_H_
 #define CHROMEOS_DBUS_SESSION_MANAGER_CLIENT_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 45 matching lines @@
     virtual void LockScreenForStub() = 0;
   };
 
   // Sets the delegate used by the stub implementation. Ownership of |delegate|
   // remains with the caller.
   virtual void SetStubDelegate(StubDelegate* delegate) = 0;
 
   // Adds and removes the observer.
   virtual void AddObserver(Observer* observer) = 0;
   virtual void RemoveObserver(Observer* observer) = 0;
-  virtual bool HasObserver(Observer* observer) = 0;
+  virtual bool HasObserver(const Observer* observer) const = 0;
 
   // Kicks off an attempt to emit the "login-prompt-visible" upstart signal.
   virtual void EmitLoginPromptVisible() = 0;
 
   // Restarts a job referenced by |pid| with the provided command line.
   virtual void RestartJob(int pid, const std::string& command_line) = 0;
 
   // Starts the session for the user.
   virtual void StartSession(const std::string& user_email) = 0;
 
@@ skipping 112 matching lines @@
   // Create() should be used instead.
   SessionManagerClient();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SessionManagerClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_SESSION_MANAGER_CLIENT_H_