Refactor extension event distribution to use Values instead of JSON strings.

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 170 matching lines @@
                              const Extension* extension,
                              size_t voice_index) {
   // See if the engine supports the "end" event; if so, we can keep the
   // utterance around and track it. If not, we're finished with this
   // utterance now.
   const std::set<std::string> event_types =
       extension->tts_voices()[voice_index].event_types;
   bool sends_end_event =
       (event_types.find(constants::kEventTypeEnd) != event_types.end());
 
-  ListValue args;
-  args.Set(0, Value::CreateStringValue(utterance->text()));
+  ListValue* args = new ListValue();
+  args->Set(0, Value::CreateStringValue(utterance->text()));
 
   // Pass through most options to the speech engine, but remove some
   // that are handled internally.
   DictionaryValue* options = static_cast<DictionaryValue*>(
       utterance->options()->DeepCopy());
   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);
+  args->Set(1, options);
+  args->Set(2, Value::CreateIntegerValue(utterance->id()));
 
   utterance->profile()->GetExtensionEventRouter()->DispatchEventToExtension(
       extension->id(),
       events::kOnSpeak,
-      json_args,
+      args,
       utterance->profile(),
       GURL());
 }
 
 void ExtensionTtsEngineStop(Utterance* utterance) {
   utterance->profile()->GetExtensionEventRouter()->DispatchEventToExtension(
       utterance->extension_id(),
       events::kOnStop,
-      "[]",
+      NULL,
       utterance->profile(),
       GURL());
 }
 
 bool ExtensionTtsEngineSendTtsEventFunction::RunImpl() {
   int utterance_id;
   std::string error_message;
   EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &utterance_id));
 
   DictionaryValue* event;
@@ skipping 44 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;
 }