Polish the keybinding implementation a bit.

chrome/common/extensions/extension_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.
 
 #ifndef CHROME_COMMON_EXTENSIONS_EXTENSION_CONSTANTS_H_
 #define CHROME_COMMON_EXTENSIONS_EXTENSION_CONSTANTS_H_
 #pragma once
 
 #include <string>
 
@@ skipping 82 matching lines @@
   extern const char kPlatformApp[];
   extern const char kPlugins[];
   extern const char kPluginsPath[];
   extern const char kPluginsPublic[];
   extern const char kPublicKey[];
   extern const char kRequirements[];
   extern const char kRunAt[];
   extern const char kShiftKey[];
   extern const char kShortcutKey[];
   extern const char kSignature[];
+  extern const char kSuggestedKeyMac[];
+  extern const char kSuggestedKeyOther[];
+  extern const char kSuggestedKeyWin[];
   extern const char kTheme[];
   extern const char kThemeColors[];
   extern const char kThemeDisplayProperties[];
   extern const char kThemeImages[];
   extern const char kThemeTints[];
   extern const char kTtsEngine[];
   extern const char kTtsGenderFemale[];
   extern const char kTtsGenderMale[];
   extern const char kTtsVoices[];
   extern const char kTtsVoicesEventTypeEnd[];
@@ skipping 397 matching lines @@
 
   enum UnloadedExtensionReason {
     UNLOAD_REASON_DISABLE,    // Extension is being disabled.
     UNLOAD_REASON_UPDATE,     // Extension is being updated to a newer version.
     UNLOAD_REASON_UNINSTALL,  // Extension is being uninstalled.
     UNLOAD_REASON_TERMINATE,  // Extension has terminated.
   };
 }  // extension_misc
 
 #endif  // CHROME_COMMON_EXTENSIONS_EXTENSION_CONSTANTS_H_