Moves maintaining root_window_for_new_windows_ to Shell

ash/test/ash_test_helper.cc

 // Copyright 2013 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/test/ash_test_helper.h"
 
 #include "ash/accelerators/accelerator_controller_delegate_aura.h"
 #include "ash/common/test/test_session_state_delegate.h"
 #include "ash/common/test/test_system_tray_delegate.h"
 #include "ash/common/test/wm_shell_test_api.h"
@@ skipping 209 matching lines @@
 }
 
 // static
 TestSessionStateDelegate* AshTestHelper::GetTestSessionStateDelegate() {
   CHECK(WmShell::HasInstance());
   return static_cast<TestSessionStateDelegate*>(
       WmShell::Get()->GetSessionStateDelegate());
 }
 
 aura::Window* AshTestHelper::CurrentContext() {
-  aura::Window* root_window = Shell::GetTargetRootWindow();
+  aura::Window* root_window = Shell::GetRootWindowForNewWindows();
   if (!root_window)
     root_window = Shell::GetPrimaryRootWindow();
   DCHECK(root_window);
   return root_window;
 }
 
 void AshTestHelper::UpdateDisplayForMash(const std::string& display_spec) {
   // TODO(erg): This is not equivalent to display::DisplayManager::
   // UpdateDisplaysWith(). This does not calculate all the internal metric
   // changes, does not calculate focus changes and does not dispatch to all the
@@ skipping 123 matching lines @@
   std::set<RootWindowController*> roots =
       window_manager_app_->window_manager()->GetRootWindowControllers();
   std::vector<RootWindowController*> ordered_roots;
   ordered_roots.insert(ordered_roots.begin(), roots.begin(), roots.end());
   std::sort(ordered_roots.begin(), ordered_roots.end(), &CompareByDisplayId);
   return ordered_roots;
 }
 
 }  // namespace test
 }  // namespace ash