Remove BrowserSignin, as it's not used anywhere.

chrome/browser/profiles/profile.h

 // Copyright (c) 2011 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.
 
 // This class gathers state related to a single user profile.
 
 #ifndef CHROME_BROWSER_PROFILES_PROFILE_H_
 #define CHROME_BROWSER_PROFILES_PROFILE_H_
 #pragma once
 
@@ skipping 36 matching lines @@
 namespace prerender {
 class PrerenderManager;
 }
 
 namespace speech_input {
 class SpeechRecognizer;
 }
 
 class AutocompleteClassifier;
 class BookmarkModel;
-class BrowserSignin;
 class ChromeAppCacheService;
 class ChromeURLDataManager;
 class Extension;
 class ExtensionDevToolsManager;
 class ExtensionEventRouter;
 class ExtensionInfoMap;
 class ExtensionMessageService;
 class ExtensionPrefValueMap;
 class ExtensionProcessManager;
 class ExtensionService;
@@ skipping 283 matching lines @@
   virtual TemplateURLFetcher* GetTemplateURLFetcher() = 0;
 
   // Returns the PersonalDataManager associated with this profile.
   virtual PersonalDataManager* GetPersonalDataManager() = 0;
 
   // Returns the FileSystemContext associated to this profile.  The context
   // is lazily created the first time this method is called.  This is owned
   // by the profile.
   virtual fileapi::FileSystemContext* GetFileSystemContext() = 0;
 
-  // Returns the BrowserSignin object assigned to this profile.
-  virtual BrowserSignin* GetBrowserSignin() = 0;
-
   // Returns the request context used for extension-related requests.  This
   // is only used for a separate cookie store currently.
   virtual net::URLRequestContextGetter* GetRequestContextForExtensions() = 0;
 
   // Returns the request context used within an installed app that has
   // requested isolated storage.
   virtual net::URLRequestContextGetter* GetRequestContextForIsolatedApp(
       const std::string& app_id) = 0;
 
   // Called by the ExtensionService that lives in this profile. Gives the
@@ skipping 213 matching lines @@
 struct hash<Profile*> {
   std::size_t operator()(Profile* const& p) const {
     return reinterpret_cast<std::size_t>(p);
   }
 };
 
 }  // namespace __gnu_cxx
 #endif
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_H_