Adds the concept of a 'safe mode' hotkey start

chrome/installer/util/browser_distribution.h

 // Copyright (c) 2012 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 file declares a class that contains various method related to branding.
 
 #ifndef CHROME_INSTALLER_UTIL_BROWSER_DISTRIBUTION_H_
 #define CHROME_INSTALLER_UTIL_BROWSER_DISTRIBUTION_H_
 
 #include <string>
@@ skipping 143 matching lines @@
   virtual void UpdateInstallStatus(bool system_install,
       installer::ArchiveType archive_type,
       installer::InstallStatus install_status);
 
   // Returns true if this distribution should set the Omaha experiment_labels
   // registry value.
   virtual bool ShouldSetExperimentLabels();
 
   virtual bool HasUserExperiments();
 
+  // Returning zero means that there is no hotkey.
+  virtual int GetSafeModeHotkey();

[robertshield, 2013/11/04 02:19:55]

should this return a uint32 instead?

[grt (UTC plus 2), 2013/11/04 15:25:14]

what about uint16 (IShellLink::SetHotkey takes a WORD)?

[cpu_(ooo_6.6-7.5), 2013/11/04 19:10:57]

Done.

Since I am not ifdefing for windows I rather keep it dword size, also seems that
RegisterHotkey (if we were to ever use it) is hard to pack in 16 bits (although
technically doable).

Going with Robert's uint32. 

+
  protected:
   explicit BrowserDistribution(Type type);
 
   template<class DistributionClass>
   static BrowserDistribution* GetOrCreateBrowserDistribution(
       BrowserDistribution** dist);
 
   const Type type_;
 
  private:
   BrowserDistribution();
 
   DISALLOW_COPY_AND_ASSIGN(BrowserDistribution);
 };
 
 #endif  // CHROME_INSTALLER_UTIL_BROWSER_DISTRIBUTION_H_