Fix WindowTreeClient::RequestClose(window_id).

ui/aura/mus/window_tree_client.cc

Index: ui/aura/mus/window_tree_client.cc
diff --git a/ui/aura/mus/window_tree_client.cc b/ui/aura/mus/window_tree_client.cc
index e9d1c0772d7a3ed3e42a9dae278a8516cec18268..0335352ed9e8e0e5c27d48669c2aa0a05f2d6a9b 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -1311,10 +1311,16 @@ void WindowTreeClient::GetWindowManager(
 
 void WindowTreeClient::RequestClose(uint32_t window_id) {
   WindowMus* window = GetWindowByServerId(window_id);
-  if (!window || !IsRoot(window))
+  if (!window)
     return;
 
-  window->GetWindow()->delegate()->OnRequestClose();
+  // If the window is the root window, we send close request to the entire
+  // WindowTreeHost. Otherwise we ask the delegate of the window to close it.
+  if (IsRoot(window)) {
+    GetWindowTreeHostMus(window->GetWindow())->OnCloseRequest();
+  } else {
+    window->GetWindow()->delegate()->OnRequestClose();
+  }

[sadrul, 2017/01/04 20:08:07]

Don't need {}

As discussed offline, the alternate is to use a delegate when creating the
root-window for the WTHostMus, and close the WTH from its OnRequestClose()
override. However, doing that would cause aura::Window::GetToplevelWindow() to
always return the root-window, which may not be what we want. So special-casing
the root window here seems like the better solution.

+sky@ for thoughts.

 }
 
 void WindowTreeClient::OnConnect(ClientSpecificId client_id) {