Pin apps from prefs on the mash shelf.

chrome/browser/ui/ash/launcher/app_tab_helper.h

+// 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.
+
+#ifndef CHROME_BROWSER_UI_ASH_LAUNCHER_APP_TAB_HELPER_H_
+#define CHROME_BROWSER_UI_ASH_LAUNCHER_APP_TAB_HELPER_H_
+
+#include <string>
+
+class Profile;
+
+namespace content {
+class WebContents;
+}
+
+// Mockable interface to get app ids from tabs.
+class AppTabHelper {

[sky, 2016/04/27 21:01:33]

I would avoid using the suffix TabHelper. TabHelper generally means you are a
content::WebContentsUserData, eg <SadTabHelper>:

class SadTabHelper : public content::WebContentsObserver,
                     public content::WebContentsUserData<SadTabHelper> {

class FindTabHelper : public content::WebContentsObserver,
                      public content::WebContentsUserData<FindTabHelper> {

[msw, 2016/04/29 22:30:49]

This was simply moving the existing class, but I've renamed it.

+ public:
+  virtual ~AppTabHelper() {}
+
+  // Returns the app id of the specified tab, or an empty string if there is
+  // no app. All known profiles will be queried for this.
+  virtual std::string GetAppID(content::WebContents* tab) = 0;
+
+  // Returns true if |id| is valid for the currently active profile.
+  // Used during restore to ignore no longer valid extensions.
+  // Note that already running applications are ignored by the restore process.
+  virtual bool IsValidIDForCurrentUser(const std::string& id) = 0;
+
+  // Sets the currently active profile for the usage of |GetAppID|.
+  virtual void SetCurrentUser(Profile* profile) = 0;
+};
+
+#endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_APP_TAB_HELPER_H_