Support creation of toplevel mus::Windows on separate displays

ash/common/wm/container_finder.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/common/wm/container_finder.h"
 
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/wm/always_on_top_controller.h"
 #include "ash/common/wm/root_window_finder.h"
 #include "ash/common/wm/window_state.h"
@@ skipping 58 matching lines @@
 
 WmWindow* GetDefaultParent(WmWindow* context,
                            WmWindow* window,
                            const gfx::Rect& bounds) {
   WmWindow* target_root = nullptr;
   WmWindow* transient_parent = window->GetTransientParent();
   if (transient_parent) {
     // Transient window should use the same root as its transient parent.
     target_root = transient_parent->GetRootWindow();
   } else {
-    target_root = FindContainerRoot(context->GetShell(), bounds);
+    target_root = context->GetRootWindow();

[mfomitchev, 2016/11/15 20:29:34]

This makes sense to me, but the original way seems like it should work too.
Perhaps we need to fix FindContainerRoot?

[thanhph, 2016/11/15 21:09:55]

If the bounds is correct, then this function FindContainerRoot is probably doing
a right thing. I think I passed in the incorrect bounds during my test case
setup or this needs to be fixed in here

https://cs.chromium.org/chromium/src/ash/mus/root_window_controller.cc?type=c...

This current patch, however, uses the context to find root window so the
incorrect bounds don't affect the root window selection (unit test correctly
passed with this fix).

+    if (!target_root)
+      target_root = FindContainerRoot(context->GetShell(), bounds);
   }
 
   switch (window->GetType()) {
     case ui::wm::WINDOW_TYPE_NORMAL:
     case ui::wm::WINDOW_TYPE_POPUP:
       if (window->IsSystemModal())
         return GetSystemModalContainer(target_root, window);
       if (HasTransientParentWindow(window))
         return GetContainerForWindow(window->GetTransientParent());
       return GetContainerFromAlwaysOnTopController(target_root, window);
@@ skipping 30 matching lines @@
     if (priority_root && priority_root->Contains(container))
       containers.insert(containers.begin(), container);
     else
       containers.push_back(container);
   }
   return containers;
 }
 
 }  // namespace wm
 }  // namespace ash