Don't dispatch event after shutdown on AshWTHUnified

ash/display/display_controller.cc

Index: ash/display/display_controller.cc
diff --git a/ash/display/display_controller.cc b/ash/display/display_controller.cc
index 2aa2fc692c0133d44c7ae02998692b4175d7aaaa..072b21de346b5037a39f4e756628a4995cbdd18f 100644
--- a/ash/display/display_controller.cc
+++ b/ash/display/display_controller.cc
@@ -631,7 +631,7 @@ bool DisplayController::UpdateWorkAreaOfDisplayNearestWindow(
 }
 
 void DisplayController::OnDisplayAdded(const gfx::Display& display) {
-  if (GetDisplayManager()->IsInUnifiedMode()) {
+  if (switches::UnifiedDesktopEnabled()) {

[oshima, 2015/04/28 07:29:41]

I made this change when cleaning up the previous CL. I somehow thought
this is equivalent, which is not.

     if (primary_display_id == gfx::Display::kInvalidDisplayID)
       primary_display_id = display.id();
     AshWindowTreeHost* ash_host =
@@ -642,6 +642,14 @@ void DisplayController::OnDisplayAdded(const gfx::Display& display) {
       AshWindowTreeHost* to_delete = primary_tree_host_for_replace_;
       primary_tree_host_for_replace_ = nullptr;
       DeleteHost(to_delete);
+#ifndef NDEBUG
+      auto iter = std::find_if(
+          window_tree_hosts_.begin(), window_tree_hosts_.end(),
+          [to_delete](const std::pair<int64, AshWindowTreeHost*>& pair) {
+            return pair.second == to_delete;
+          });
+      DCHECK(iter == window_tree_hosts_.end());
+#endif
       // the host has already been removed from the window_tree_host_.
     }
   }