Add skeleton for select-to-speak component extension.

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_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 180 matching lines @@
   APP_LAUNCH_BUCKET_INVALID
 };
 
 // The extension id of the ChromeVox extension.
 extern const char kChromeVoxExtensionId[];
 
 #if defined(OS_CHROMEOS)
 // Path to preinstalled ChromeVox screen reader extension (relative to
 // |chrome::DIR_RESOURCES|).
 extern const char kChromeVoxExtensionPath[];
+// The extension id of the Select-to-speak extension.
+extern const char kSelectToSpeakExtensionId[];
+// Path to preinstalled Select-to-speak extension (relative to
+// |chrome::DIR_RESOURCES|).
+extern const char kSelectToSpeakExtensionPath[];
 // Name of the manifest file in an extension when a special manifest is used
 // for guest mode.
 extern const char kGuestManifestFilename[];
 // Extension id, path (relative to |chrome::DIR_RESOURCES|) and IME engine
 // id for the builtin-in Braille IME extension.
 extern const char kBrailleImeExtensionId[];
 extern const char kBrailleImeExtensionPath[];
 extern const char kBrailleImeEngineId[];
 // Path to preinstalled Connectivity Diagnostics extension.
 extern const char kConnectivityDiagnosticsPath[];
@@ skipping 40 matching lines @@
 extern const int kWebstoreSignaturesPublicKeySize;
 
 #if defined(OS_CHROMEOS)
 // Returns true if |extension_id| is one of the IME extensions that will create
 // IME menu.
 bool IsImeMenuExtensionId(const std::string& extension_id);
 #endif
 }  // namespace extension_misc
 
 #endif  // CHROME_COMMON_EXTENSIONS_EXTENSION_CONSTANTS_H_