Introduce AppsClient and use it in apps to get the loaded profiles list.

chrome/browser/apps/chrome_apps_client.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 "chrome/browser/apps/chrome_apps_client.h"
+
+#include "base/memory/singleton.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/profiles/profile_manager.h"
+
+ChromeAppsClient::ChromeAppsClient() {}
+
+ChromeAppsClient::~ChromeAppsClient() {}
+
+// static
+ChromeAppsClient* ChromeAppsClient::GetInstance() {
+  return Singleton<ChromeAppsClient,
+                   LeakySingletonTraits<ChromeAppsClient> >::get();
+}
+
+std::vector<content::BrowserContext*>
+    ChromeAppsClient::GetLoadedBrowserContexts() {
+  std::vector<Profile*> profiles =
+      g_browser_process->profile_manager()->GetLoadedProfiles();
+  return std::vector<content::BrowserContext*>(profiles.begin(),
+                                               profiles.end());
+}