Add default icon to app_host.exe, and use it in shortcuts during installation.

chrome/installer/util/google_chrome_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 extends generic BrowserDistribution class to declare Google Chrome
 // specific implementation.
 
 #ifndef CHROME_INSTALLER_UTIL_GOOGLE_CHROME_DISTRIBUTION_H_
 #define CHROME_INSTALLER_UTIL_GOOGLE_CHROME_DISTRIBUTION_H_
 
@@ skipping 56 matching lines @@
   // potential use in the uninstall survey. It must be called before the
   // key returned by GetVersionKey() is deleted.
   virtual string16 GetDistributionData(HKEY root_key) OVERRIDE;
 
   virtual string16 GetUninstallLinkName() OVERRIDE;
 
   virtual string16 GetUninstallRegPath() OVERRIDE;
 
   virtual string16 GetVersionKey() OVERRIDE;
 
+  virtual string16 GetIconFilename() OVERRIDE;
+
   virtual bool GetCommandExecuteImplClsid(
       string16* handler_class_uuid) OVERRIDE;
 
   virtual void UpdateInstallStatus(
       bool system_install,
       installer::ArchiveType archive_type,
       installer::InstallStatus install_status) OVERRIDE;
 
   virtual bool GetExperimentDetails(UserExperiment* experiment,
                                     int flavor) OVERRIDE;
@@ skipping 44 matching lines @@
   // Returns true if at least one uninstall metric was found in
   // uninstall_metrics_dict, false otherwise.
   virtual bool BuildUninstallMetricsString(
       const base::DictionaryValue* uninstall_metrics_dict, string16* metrics);
 
   // The product ID for Google Update.
   string16 product_guid_;
 };
 
 #endif  // CHROME_INSTALLER_UTIL_GOOGLE_CHROME_DISTRIBUTION_H_