Hook up Chrome's wallpaper picker for mash.

chrome/browser/chromeos/extensions/wallpaper_private_api.cc

 // Copyright (c) 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 "chrome/browser/chromeos/extensions/wallpaper_private_api.h"
 
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
@@ skipping 151 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(WindowStateManager);
 };
 
 // static
 WindowStateManager* g_window_state_manager = NULL;
 
 // static
 void WindowStateManager::MinimizeInactiveWindows(
     const std::string& user_id_hash) {
+  if (!ash::Shell::HasInstance() || ash::Shell::GetInstance()->in_mus()) {

[sadrul, 2016/05/19 19:45:22]

If there's a Shell instance, it should never have in_mus() set here. i.e. the
in_mus() check shouldn't be needed.

You could also check chrome::IsRunningInMash() instead.

[msw, 2016/05/19 20:22:17]

Done.

+    NOTIMPLEMENTED();
+    return;
+  }
+
   if (!g_window_state_manager)
     g_window_state_manager = new WindowStateManager();
   g_window_state_manager->BuildWindowListAndMinimizeInactiveForUser(
       user_id_hash, ash::wm::GetActiveWindow());
 }
 
 // static
 void WindowStateManager::RestoreWindows(const std::string& user_id_hash) {
+  if (!ash::Shell::HasInstance() || ash::Shell::GetInstance()->in_mus()) {
+    NOTIMPLEMENTED();
+    return;
+  }
+
   if (!g_window_state_manager) {
     DCHECK(false) << "This should only be called after calling "
                   << "MinimizeInactiveWindows.";
     return;
   }
 
   g_window_state_manager->RestoreMinimizedWindows(user_id_hash);
   if (g_window_state_manager->user_id_hash_window_list_map_.empty()) {
     delete g_window_state_manager;
     g_window_state_manager = NULL;
@@ skipping 773 matching lines @@
 bool WallpaperPrivateRecordWallpaperUMAFunction::RunSync() {
   std::unique_ptr<record_wallpaper_uma::Params> params(
       record_wallpaper_uma::Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params);
 
   user_manager::User::WallpaperType source = getWallpaperType(params->source);
   UMA_HISTOGRAM_ENUMERATION("Ash.Wallpaper.Source", source,
                             user_manager::User::WALLPAPER_TYPE_COUNT);
   return true;
 }