Adds support for multiple displays to WmTestBase

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 163 matching lines @@
   RootWindowController* root_window_controller =
       root_window_controller_ptr.get();
   root_window_controllers_.insert(std::move(root_window_controller_ptr));
   window->AddObserver(this);
 
   FOR_EACH_OBSERVER(WindowManagerObserver, observers_,
                     OnRootWindowControllerAdded(root_window_controller));
   return root_window_controller;
 }
 
+void WindowManager::RemoveDisplay(ui::Window* window) {

[msw, 2016/09/12 22:01:51]

q: just window->Destroy and let OnWindowDestroy[ing|ed] do the rest?
(I see you want to move away from that pattern, so maybe it's okay to support
both and leave this as-is for now... just more code!)

[sky, 2016/09/12 23:11:27]

Indeed. I want to move away from the observer and prefer this approach.

+  // TODO(sky): WindowManager shouldn't need to observer the windows. Instead

[msw, 2016/09/12 22:01:51]

nit: "observer"

[sky, 2016/09/12 23:11:27]

Done.

+  // WindowManager should have a specific API that is called when a display is
+  // removed.
+  auto it = FindRootWindowControllerByWindow(window);
+  DCHECK(it != root_window_controllers_.end());
+  FOR_EACH_OBSERVER(WindowManagerObserver, observers_,
+                    OnWillDestroyRootWindowController((*it).get()));
+  root_window_controllers_.erase(it);
+  // Remove the observer so we don't see the OnWindowDestroying/Destroyed as we
+  // already handled it here.
+  window->RemoveObserver(this);
+  window->Destroy();
+}
+
 void WindowManager::Shutdown() {
   if (!window_tree_client_)
     return;
 
   // Observers can rely on WmShell from the callback. So notify the observers
   // before destroying it.
   FOR_EACH_OBSERVER(WindowManagerObserver, observers_,
                     OnWindowTreeClientDestroyed());
 
   // Destroy the roots of the RootWindowControllers, which triggers removal
   // in OnWindowDestroyed().
   while (!root_window_controllers_.empty())
     (*root_window_controllers_.begin())->root()->Destroy();
 
   lookup_.reset();
   shell_->Shutdown();
   shell_.reset();
   shadow_controller_.reset();
 
   pointer_watcher_event_router_.reset();
 
   window_tree_client_.reset();
   window_manager_client_ = nullptr;
 }
 
-void WindowManager::OnWindowDestroying(ui::Window* window) {
+WindowManager::RootWindowControllers::iterator
+WindowManager::FindRootWindowControllerByWindow(ui::Window* window) {
   for (auto it = root_window_controllers_.begin();

[msw, 2016/09/12 22:01:51]

optional nit: for (auto it : root_window_controllers_) {

[sky, 2016/09/12 23:11:27]

That'll give me a std::unique_ptr<RootWindowController*>&. I want the iterator.

        it != root_window_controllers_.end(); ++it) {
-    if ((*it)->root() == window) {
-      FOR_EACH_OBSERVER(WindowManagerObserver, observers_,
-                        OnWillDestroyRootWindowController((*it).get()));
-      return;
-    }
+    if ((*it)->root() == window)
+      return it;
   }
-  NOTREACHED();
+  return root_window_controllers_.end();
+}
+
+void WindowManager::OnWindowDestroying(ui::Window* window) {
+  auto it = FindRootWindowControllerByWindow(window);
+  DCHECK(it != root_window_controllers_.end());
+  FOR_EACH_OBSERVER(WindowManagerObserver, observers_,
+                    OnWillDestroyRootWindowController((*it).get()));
 }
 
 void WindowManager::OnWindowDestroyed(ui::Window* window) {
+  auto it = FindRootWindowControllerByWindow(window);
+  DCHECK(it != root_window_controllers_.end());
   window->RemoveObserver(this);
-  for (auto it = root_window_controllers_.begin();
-       it != root_window_controllers_.end(); ++it) {
-    if ((*it)->root() == window) {
-      root_window_controllers_.erase(it);
-      return;
-    }
-  }
-  NOTREACHED();
+  root_window_controllers_.erase(it);
 }
 
 void WindowManager::OnEmbed(ui::Window* root) {
   // WindowManager should never see this, instead OnWmNewDisplay() is called.
   NOTREACHED();
 }
 
 void WindowManager::OnEmbedRootDestroyed(ui::Window* root) {
   // WindowManager should never see this.
   NOTREACHED();
@@ skipping 83 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