Remove BrowserSignin, as it's not used anywhere.

chrome/browser/browser_signin.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.
-
-#ifndef CHROME_BROWSER_BROWSER_SIGNIN_H_
-#define CHROME_BROWSER_BROWSER_SIGNIN_H_
-#pragma once
-
-#include <string>
-
-#include "base/memory/scoped_ptr.h"
-#include "chrome/common/net/gaia/google_service_auth_error.h"
-#include "content/common/notification_observer.h"
-#include "content/common/notification_registrar.h"
-
-class BrowserSigninHtml;
-class Profile;
-class ProfileSyncService;
-class TabContents;
-
-// The BrowserSignin class provides a login screen which allows the
-// user to signin to the browser.  Currently the signin is coordinated
-// through the Chrome Sync logic.
-//
-// TODO(johnnyg): Separate this from the sync logic and make it the
-// sole co-ordinator of browser signin.
-//
-// This class should only be accessed on the UI thread.
-class BrowserSignin : public NotificationObserver {
- public:
-  explicit BrowserSignin(Profile* profile);
-  virtual ~BrowserSignin();
-
-  // The delegate class is invoked on success and failure.
-  class SigninDelegate {
-   public:
-    virtual ~SigninDelegate() {}
-
-    // The login was successful.
-    virtual void OnLoginSuccess() = 0;
-
-    // The login failed.
-    virtual void OnLoginFailure(const GoogleServiceAuthError& error) = 0;
-  };
-
-  // Request that the user signin, modal to TabContents provided.
-  // If a user is already signed in, this will show a login dialog where
-  // the username is not editable.
-  //
-  // A custom HTML string can be provided that will be displayed next
-  // to the signin dialog.
-  //
-  // Only one sign-in can be in process at a time; if there is one in
-  // progress already it will be canceled in favor of this one.
-  //
-  // The delegate will eventually be called with OnLoginSuccess() or
-  // OnLoginFailure(), but never both.  virtual for test override.
-  virtual void RequestSignin(TabContents* tab_contents,
-                             const string16& suggested_email,
-                             const string16& login_message,
-                             SigninDelegate* delegate);
-
-  // Returns the username of the user currently signed in.  If no
-  // user is signed in, returns the empty string.  virtual for test
-  // override.
-  virtual std::string GetSignedInUsername() const;
-
-  // NotificationObserver implementation.
-  virtual void Observe(int type,
-                       const NotificationSource& source,
-                       const NotificationDetails& details);
-
-  ProfileSyncService* GetProfileSyncService() const;
-
-  // Close the dialog.  Delegate's OnLoginFailure method will be called.
-  void Cancel();
-
- private:
-  // Create the HTML Dialog content.
-  BrowserSigninHtml* CreateHtmlDialogUI();
-
-  // When the dialog is closed.
-  void OnLoginFinished();
-
-  // Turn auth notifications on.
-  void RegisterAuthNotifications();
-
-  // Turn auth notifications off.
-  void UnregisterAuthNotifications();
-
-  // Show the dialog Tab-Modal.
-  void ShowSigninTabModal(TabContents* tab_contents);
-
-  // Non-owned pointer to the profile (which owns this object).
-  Profile* profile_;
-
-  // Suggested email for the current login prompt.
-  string16 suggested_email_;
-
-  // Current login message.
-  string16 login_message_;
-
-  // Delegate for the current sign in request.
-  SigninDelegate* delegate_;
-
-  // Current HTML Dialog information.  Pointer is owned by the WebUI it will be
-  // attached to.
-  BrowserSigninHtml* html_dialog_ui_delegate_;
-
-  NotificationRegistrar registrar_;
-
-  DISALLOW_COPY_AND_ASSIGN(BrowserSignin);
-};
-
-
-#endif  // CHROME_BROWSER_BROWSER_SIGNIN_H_