chromeos: Remove references to UnlockScreenFailed signal.

chrome/browser/chromeos/system/ash_system_tray_delegate.cc

Index: chrome/browser/chromeos/system/ash_system_tray_delegate.cc
diff --git a/chrome/browser/chromeos/system/ash_system_tray_delegate.cc b/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
index 49335da19509a23874a468d3ee091d9e0cb0eb95..ae77fccc9316471cf60e2798ed2d0b5dd0984fb1 100644
--- a/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
+++ b/chrome/browser/chromeos/system/ash_system_tray_delegate.cc
@@ -963,9 +963,6 @@ class SystemTrayDelegate : public ash::SystemTrayDelegate,
         UpdateAfterLoginStatusChange(GetUserLoginStatus());
   }
 
-  virtual void UnlockScreenFailed() OVERRIDE {
-  }
-
   // TODO(sad): Override more from PowerManagerClient::Observer here (e.g.
   // PowerButtonStateChanged etc.).