Converts most of WorkspaceLayoutManager tests to use common code

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 02e84543e1c1198ef5df84e0ecbecbea0316fab0..6e1d0baffc009402e6a18617503874732ee8d622 100644
--- a/ash/test/test_session_state_delegate.h
+++ b/ash/test/test_session_state_delegate.h
@@ -70,7 +70,7 @@ class TestSessionStateDelegate : public SessionStateDelegate {
   // Updates the internal state that indicates whether the screen can be locked.
   // Locking will only actually be allowed when this value is |true| and there
   // is an active user.
-  void SetCanLockScreen(bool can_lock_screen);
+  static void SetCanLockScreen(bool can_lock_screen);
 
   // Updates |should_lock_screen_before_suspending_|.
   void SetShouldLockScreenBeforeSuspending(bool should_lock);