Converts test_wm to use aura

ui/aura/mus/focus_synchronizer.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 "ui/aura/mus/focus_synchronizer.h"
 
 #include "base/auto_reset.h"
 #include "services/ui/public/interfaces/window_tree.mojom.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/env.h"
@@ skipping 15 matching lines @@
 }
 
 void FocusSynchronizer::SetFocusFromServer(WindowMus* window) {
   if (focused_window_ == window)
     return;
 
   DCHECK(!setting_focus_);
   base::AutoReset<bool> focus_reset(&setting_focus_, true);
   base::AutoReset<WindowMus*> window_setting_focus_to_reset(
       &window_setting_focus_to_, window);
-  Env* env = aura::Env::GetInstance();
+  Env* env = Env::GetInstance();
   if (window) {
     Window* root = window->GetWindow()->GetRootWindow();
+    // The client should provide a focus client for all roots.
+    DCHECK(client::GetFocusClient(root));
     if (env->active_focus_client_root() != root)
-      env->SetActiveFocusClient(aura::client::GetFocusClient(root), root);
+      env->SetActiveFocusClient(client::GetFocusClient(root), root);
     window->GetWindow()->Focus();
   } else if (env->active_focus_client()) {
     env->active_focus_client()->FocusWindow(nullptr);
   }
 }
 
 void FocusSynchronizer::OnFocusedWindowDestroyed() {
   focused_window_ = nullptr;
 }
 
@@ skipping 38 matching lines @@
   if (focus_client) {
     Window* focused_window = focus_client->GetFocusedWindow();
     SetFocusedWindow(focused_window ? WindowMus::Get(focused_window)
                                     : WindowMus::Get(window));
   } else {
     SetFocusedWindow(nullptr);
   }
 }
 
 }  // namespace aura