Move avatar holder code to ash

ash/test/test_session_state_delegate.h

Index: ash/test/test_session_state_delegate.h
diff --git a/ash/test/test_session_state_delegate.h b/ash/test/test_session_state_delegate.h
index 1277a068d4334777bda8d9073cb0a2116d40e4b1..21c34f61fc0257b31185cd67077d7b8875a5a29f 100644
--- a/ash/test/test_session_state_delegate.h
+++ b/ash/test/test_session_state_delegate.h
@@ -22,6 +22,8 @@ class TestSessionStateDelegate : public SessionStateDelegate {
   const std::string& get_activated_user() { return activated_user_; }
 
   // SessionStateDelegate:
+  virtual content::BrowserContext* GetBrowserContextByIndex(
+      MultiProfileIndex index) OVERRIDE;
   virtual int GetMaximumNumberOfLoggedInUsers() const OVERRIDE;
   virtual int NumberOfLoggedInUsers() const OVERRIDE;
   virtual bool IsActiveUserSessionStarted() const OVERRIDE;
@@ -38,8 +40,8 @@ class TestSessionStateDelegate : public SessionStateDelegate {
   virtual const std::string GetUserID(
       ash::MultiProfileIndex index) const OVERRIDE;
   virtual const gfx::ImageSkia& GetUserImage(
-      ash::MultiProfileIndex index) const OVERRIDE;
-  virtual void GetLoggedInUsers(UserIdList* users) OVERRIDE;
+      content::BrowserContext* context) const OVERRIDE;
+  virtual bool ShouldShowAvatar(aura::Window* window) OVERRIDE;
   virtual void SwitchActiveUser(const std::string& user_id) OVERRIDE;
   virtual void CycleActiveUser(CycleUser cycle_user) OVERRIDE;
   virtual void AddSessionStateObserver(