Add ShellIntegration::ActivateMetroChrome, which launches Chrome in metro-mode on Windows 8.

chrome/common/chrome_constants.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.
 
 // A handful of resource-like constants related to the Chrome application.
 
 #ifndef CHROME_COMMON_CHROME_CONSTANTS_H_
 #define CHROME_COMMON_CHROME_CONSTANTS_H_
 #pragma once
 
@@ skipping 21 matching lines @@
 // This is a NULL-terminated array of strings. If kHelperFlavorSuffixes
 // contains "EN", "MF", and NULL, it indicates that if the normal helper is
 // named Chromium Helper.app, helper executables could show up at any of
 // Chromium Helper.app/Contents/MacOS/Chromium Helper,
 // Chromium Helper EN.app/Contents/MacOS/Chromium Helper EN, and
 // Chromium Helper MF.app/Contents/MacOS/Chromium Helper MF.
 extern const FilePath::CharType* const kHelperFlavorSuffixes[];
 #endif  // OS_MACOSX
 extern const wchar_t kBrowserAppName[];
 #if defined(OS_WIN)
+extern const FilePath::CharType kMetroDriverDll[];
 extern const wchar_t kStatusTrayWindowClass[];
 #endif  // defined(OS_WIN)
 extern const wchar_t kMessageWindowClass[];
 extern const wchar_t kCrashReportLog[];
 extern const wchar_t kTestingInterfaceDLL[];
 extern const char    kInitialProfile[];
 extern const char    kMultiProfileDirPrefix[];
 extern const wchar_t kBrowserResourcesDll[];
 extern const wchar_t kNaClAppName[];
 extern const FilePath::CharType kExtensionFileExtension[];
@@ skipping 85 matching lines @@
 extern const wchar_t kMetroChromeUserDataSubDir[];
 // Used by Metro Chrome to initiate navigation and search requests.
 extern const wchar_t kMetroNavigationAndSearchMessage[];
 // Used by Metro Chrome to get information about the current tab.
 extern const wchar_t kMetroGetCurrentTabInfoMessage[];
 #endif
 
 }  // namespace chrome
 
 #endif  // CHROME_COMMON_CHROME_CONSTANTS_H_