Support onvoiceschanged for extension-based tts engines.

chrome/chrome_browser.gypi

 # Copyright 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.
 
 {
   'variables': {
     # All .cc, .h, .m, and .mm files under browser except for:
     # * tests and mocks.
     # * code below browser/chromeos
     # * code below browser/extensions
@@ skipping 1306 matching lines @@
       'browser/signin/signin_promo.h',
       'browser/site_details.cc',
       'browser/site_details.h',
       'browser/speech/chrome_speech_recognition_manager_delegate.cc',
       'browser/speech/chrome_speech_recognition_manager_delegate.h',
       'browser/speech/tts_android.cc',
       'browser/speech/tts_android.h',
       'browser/speech/tts_chromeos.cc',
       'browser/speech/tts_controller.cc',
       'browser/speech/tts_controller.h',
-      'browser/speech/tts_extension_loader_chromeos.cc',
-      'browser/speech/tts_extension_loader_chromeos.h',
+      'browser/speech/tts_engine_extension_observer.cc',
+      'browser/speech/tts_engine_extension_observer.h',
       'browser/speech/tts_mac.mm',
       'browser/speech/tts_platform.cc',
       'browser/speech/tts_platform.h',
       'browser/speech/tts_message_filter.cc',
       'browser/speech/tts_message_filter.h',
       'browser/speech/tts_win.cc',
       'browser/ssl/ssl_blocking_page.cc',
       'browser/ssl/ssl_blocking_page.h',
       'browser/ssl/ssl_client_certificate_selector.h',
       'browser/ssl/ssl_error_info.cc',
@@ skipping 2242 matching lines @@
             'package_name': 'org/chromium/chrome/browser',
             'template_deps': ['browser/android/tab_load_status.h'],
           },
           'includes': [ '../build/android/java_cpp_template.gypi' ],
         },
       ],
      },
     ],
   ],
 }