Fix TTS code to be compatible with new extension API parameter serialization.

chrome/browser/speech/extension_api/tts_extension_api_constants.cc

 // 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.
 
 #include "chrome/browser/speech/extension_api/tts_extension_api_constants.h"
 
 namespace tts_extension_api_constants {
 
 const char kVoiceNameKey[] = "voiceName";
 const char kLangKey[] = "lang";
 const char kGenderKey[] = "gender";
 const char kRateKey[] = "rate";
 const char kPitchKey[] = "pitch";
 const char kVolumeKey[] = "volume";
 const char kEnqueueKey[] = "enqueue";
 const char kEventTypeKey[] = "type";
 const char kEventTypesKey[] = "eventTypes";
 const char kCharIndexKey[] = "charIndex";
 const char kErrorMessageKey[] = "errorMessage";
 const char kRequiredEventTypesKey[] = "requiredEventTypes";
 const char kDesiredEventTypesKey[] = "desiredEventTypes";
 const char kExtensionIdKey[] = "extensionId";
 const char kSrcIdKey[] = "srcId";
 const char kIsFinalEventKey[] = "isFinalEvent";
+const char kOnEventKey[] = "onEvent";
 
 const char kGenderFemale[] = "female";
 const char kGenderMale[] = "male";
 
 const char kEventTypeStart[] = "start";
 const char kEventTypeEnd[] = "end";
 const char kEventTypeWord[] = "word";
 const char kEventTypeSentence[] = "sentence";
 const char kEventTypeMarker[] = "marker";
 const char kEventTypeInterrupted[] = "interrupted";
 const char kEventTypeCancelled[] = "cancelled";
 const char kEventTypeError[] = "error";
 
 const char kNativeVoiceName[] = "native";
 
 const char kErrorUndeclaredEventType[] =
     "Cannot send an event type that is not declared in the extension manifest.";
 const char kErrorUtteranceTooLong[] = "Utterance length is too long.";
 const char kErrorInvalidLang[] = "Invalid lang.";
 const char kErrorInvalidGender[] = "Invalid gender.";
 const char kErrorInvalidRate[] = "Invalid rate.";
 const char kErrorInvalidPitch[] = "Invalid pitch.";
 const char kErrorInvalidVolume[] = "Invalid volume.";
 
 }  // namespace tts_extension_api_constants.