Handle modified displays in mustash.

ash/mus/window_manager.cc

 // Copyright 2015 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/mus/window_manager.h"
 
 #include <stdint.h>
 
 #include <utility>
 
@@ skipping 315 matching lines @@
                                    const display::Display& display) {
   CreateRootWindowController(window, display);
 }
 
 void WindowManager::OnWmDisplayRemoved(ui::Window* window) {
   auto iter = FindRootWindowControllerByWindow(window);
   DCHECK(iter != root_window_controllers_.end());
   DestroyRootWindowController(iter->get());
 }
 
+void WindowManager::OnWmDisplayModified(const display::Display& display) {
+  for (auto& controller : root_window_controllers_) {
+    if (controller->display().id() == display.id()) {
+      controller->set_display(display);

[sky, 2016/10/19 23:37:59]

Can you make set_display() call to UpdateDisplay()? Otherwise it's easy to miss
the call to UpdateDisplay, and it's wierd that this code updates the displaylist
but RootWindowController::SetWorkAreaInests does it as well.

[kylechar, 2016/10/20 15:04:19]

I could do that. In general it seems wrong to me that
RootWindowController::display_ exists in the first place. Screen has a copy of
Display and the two copes need to be identical. So it's twice the memory and
more code to keep them in sync.

It seems like lots of mash_unittests rely on RootWindowController::display_
existing though. So maybe I could remove it in a followup CL?

[sky, 2016/10/20 15:33:24]

Good point. I would still think RootWindowController should be the one updated
screen though as it does that in other places.

[kylechar, 2016/10/20 18:31:29]

Done.

+      screen_->display_list()->UpdateDisplay(display);
+      // The root window will be resized by the window server.
+      return;
+    }
+  }
+
+  NOTREACHED();
+}
+
 void WindowManager::OnWmPerformMoveLoop(
     ui::Window* window,
     ui::mojom::MoveLoopSource source,
     const gfx::Point& cursor_location,
     const base::Callback<void(bool)>& on_done) {
   WmWindowMus* child_window = WmWindowMus::Get(window);
   MoveEventHandler* handler = MoveEventHandler::GetForWindow(child_window);
   if (!handler) {
     on_done.Run(false);
     return;
@@ skipping 18 matching lines @@
                                                     const ui::Event& event) {
   auto iter = accelerator_handlers_.find(GetAcceleratorNamespaceId(id));
   if (iter == accelerator_handlers_.end())
     return ui::mojom::EventResult::HANDLED;
 
   return iter->second->OnAccelerator(id, event);
 }
 
 }  // namespace mus
 }  // namespace ash