Add WM_EVENT_TRUSTED_PIN and WINDOW_STATE_TYPE_TRUSTED_PINNED to Ash.

ash/wm/window_util.cc

Index: ash/wm/window_util.cc
diff --git a/ash/wm/window_util.cc b/ash/wm/window_util.cc
index 9cf50d32120034195e23230d032b26d5a36a0c0d..d81105b4c86ee76f3bb32fbffc995b4c59ff6bc8 100644
--- a/ash/wm/window_util.cc
+++ b/ash/wm/window_util.cc
@@ -62,8 +62,8 @@ bool IsWindowUserPositionable(aura::Window* window) {
   return GetWindowState(window)->IsUserPositionable();
 }
 
-void PinWindow(aura::Window* window) {
-  wm::WMEvent event(wm::WM_EVENT_PIN);
+void PinWindow(aura::Window* window, bool trusted) {
+  wm::WMEvent event(trusted ? wm::WM_EVENT_TRUSTED_PIN : wm::WM_EVENT_PIN);
   wm::GetWindowState(window)->OnWMEvent(&event);
 }