Add WM_EVENT_TRUSTED_PIN and WINDOW_STATE_TYPE_TRUSTED_PINNED to Ash.

ash/common/wm/wm_event.h

Index: ash/common/wm/wm_event.h
diff --git a/ash/common/wm/wm_event.h b/ash/common/wm/wm_event.h
index 6e41596fca6f24785c16499d4e20412ec9c77a08..e26ba78d46a83d1b66ef46185323a2a90b672cfa 100644
--- a/ash/common/wm/wm_event.h
+++ b/ash/common/wm/wm_event.h
@@ -91,6 +91,10 @@ enum WMEventType {
 
   // A user requested to pin a window.
   WM_EVENT_PIN,
+
+  // A user requested to pin a window for a trusted application. This is similar
+  // WM_EVENT_PIN but does not allow user to exit the mode by shortcut key.
+  WM_EVENT_TRUSTED_PIN,
 };
 
 class ASH_EXPORT WMEvent {