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..8dfa740eb9578c2fbdec1aabf9a9c8579bd7d506 100644
--- a/ash/display/display_controller.cc
+++ b/ash/display/display_controller.cc
@@ -631,7 +631,8 @@ bool DisplayController::UpdateWorkAreaOfDisplayNearestWindow(
 }
 
 void DisplayController::OnDisplayAdded(const gfx::Display& display) {
-  if (GetDisplayManager()->IsInUnifiedMode()) {
+#if defined(OS_CHROMEOS)
+  if (switches::UnifiedDesktopEnabled()) {

[Jun Mukai, 2015/04/28 17:07:39]

Does this mean it's always in the unified desktop mode once the flag is set and
cannot be changed?  Is that intentional?

[oshima, 2015/04/28 17:10:18]

That's a flag, so you can't change it on the fly anyway. I have a plan to
consolidate but not in m44. (see my comment at 658)

[oshima, 2015/04/28 17:20:20]

Actually, I should check the default multi display mode. Uploaded new patch.
PTAL.

     if (primary_display_id == gfx::Display::kInvalidDisplayID)
       primary_display_id = display.id();
     AshWindowTreeHost* ash_host =
@@ -642,13 +643,22 @@ 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_.
     }
-  }
+  } else
+#endif
   // TODO(oshima): It should be possible to consolidate logic for
   // unified and non unified, but I'm keeping them separated to minimize
   // the risk in M44. I'll consolidate this in M45.
-  else if (primary_tree_host_for_replace_) {
+  if (primary_tree_host_for_replace_) {
     DCHECK(window_tree_hosts_.empty());
     primary_display_id = display.id();
     window_tree_hosts_[display.id()] = primary_tree_host_for_replace_;