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

chrome/browser/speech/extension_api/tts_engine_extension_api.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_engine_extension_api.h"
 
 #include <string>
 
 #include "base/json/json_writer.h"
 #include "base/values.h"
@@ skipping 163 matching lines @@
   if (options->HasKey(constants::kRequiredEventTypesKey))
     options->Remove(constants::kRequiredEventTypesKey, NULL);
   if (options->HasKey(constants::kDesiredEventTypesKey))
     options->Remove(constants::kDesiredEventTypesKey, NULL);
   if (sends_end_event && options->HasKey(constants::kEnqueueKey))
     options->Remove(constants::kEnqueueKey, NULL);
   if (options->HasKey(constants::kSrcIdKey))
     options->Remove(constants::kSrcIdKey, NULL);
   if (options->HasKey(constants::kIsFinalEventKey))
     options->Remove(constants::kIsFinalEventKey, NULL);
+  if (options->HasKey(constants::kOnEventKey))
+    options->Remove(constants::kOnEventKey, NULL);
 
   args.Set(1, options);
   args.Set(2, Value::CreateIntegerValue(utterance->id()));
   std::string json_args;
   base::JSONWriter::Write(&args, &json_args);
 
   utterance->profile()->GetExtensionEventRouter()->DispatchEventToExtension(
       extension->id(),
       events::kOnSpeak,
       json_args,
@@ skipping 63 matching lines @@
     std::string error_message;
     event->GetString(constants::kErrorMessageKey, &error_message);
     controller->OnTtsEvent(
         utterance_id, TTS_EVENT_ERROR, char_index, error_message);
   } else {
     EXTENSION_FUNCTION_VALIDATE(false);
   }
 
   return true;
 }