Support additional mash shelf alignments.

mash/wm/root_window_controller.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 "mash/wm/root_window_controller.h"
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "components/mus/common/util.h"
@@ skipping 73 matching lines @@
   switch (id) {
     case kWindowSwitchAccelerator:
       window_manager_client()->ActivateNextWindow();
       break;
     default:
       app_->OnAccelerator(id, event);
       break;
   }
 }
 
+ShelfLayout* RootWindowController::GetShelfLayoutManager() {
+  return static_cast<ShelfLayout*>(
+      layout_manager_[GetWindowForContainer(mojom::Container::USER_SHELF)]
+          .get());
+}
+
 RootWindowController::RootWindowController(WindowManagerApplication* app)
     : app_(app), root_(nullptr), window_count_(0) {
   window_manager_.reset(new WindowManager);
 }
 
 RootWindowController::~RootWindowController() {}
 
 void RootWindowController::AddAccelerators() {
   window_manager_client()->AddAccelerator(
       kWindowSwitchAccelerator,
@@ skipping 91 matching lines @@
   CreateContainer(mojom::Container::BUBBLES, mojom::Container::ROOT);
   CreateContainer(mojom::Container::SYSTEM_MODAL_WINDOWS,
                   mojom::Container::ROOT);
   CreateContainer(mojom::Container::KEYBOARD, mojom::Container::ROOT);
   CreateContainer(mojom::Container::MENUS, mojom::Container::ROOT);
   CreateContainer(mojom::Container::TOOLTIPS, mojom::Container::ROOT);
 }
 
 }  // namespace wm
 }  // namespace mash