Remove stops_event_propagation from Window, since it's broken.

ash/shell_delegate.h

Index: ash/shell_delegate.h
===================================================================
--- ash/shell_delegate.h	(revision 128508)
+++ ash/shell_delegate.h	(working copy)
@@ -54,11 +54,15 @@
   // until e.g. a user has logged in and their profile has been loaded.
   virtual bool CanCreateLauncher() = 0;
 
-#if defined(OS_CHROMEOS)
-  // Invoked when a user uses Ctrl-Shift-L to lock the screen.
+  // Invoked when a user locks the screen.
   virtual void LockScreen() = 0;
-#endif
 
+  // Unlock the screen. Currently used only for tests.
+  virtual void UnlockScreen() = 0;
+
+  // Returns true if the screen is currently locked.
+  virtual bool IsScreenLocked() const = 0;
+
   // Invoked when a user uses Ctrl-Shift-Q to close chrome.
   virtual void Exit() = 0;