arc: Convert more Mojo types to STL

chrome/browser/chromeos/arc/tts/arc_tts_service.cc

 // Copyright 2016 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/chromeos/arc/tts/arc_tts_service.h"
 
 #include "base/logging.h"
 #include "chrome/browser/speech/tts_controller.h"
 #include "components/arc/arc_bridge_service.h"
 
@@ skipping 11 matching lines @@
 void ArcTtsService::OnInstanceReady() {
   mojom::TtsInstance* tts_instance =
       arc_bridge_service()->tts()->GetInstanceForMethod("Init");
   DCHECK(tts_instance);
   tts_instance->Init(binding_.CreateInterfacePtrAndBind());
 }
 
 void ArcTtsService::OnTtsEvent(uint32_t id,
                                mojom::TtsEventType event_type,
                                uint32_t char_index,
-                               const mojo::String& error_msg) {
+                               const std::string& error_msg) {
   if (!TtsController::GetInstance())
     return;
 
   TtsEventType chrome_event_type;
   switch (event_type) {
     case mojom::TtsEventType::START:
       chrome_event_type = TTS_EVENT_START;
       break;
     case mojom::TtsEventType::END:
       chrome_event_type = TTS_EVENT_END;
       break;
     case mojom::TtsEventType::INTERRUPTED:
       chrome_event_type = TTS_EVENT_INTERRUPTED;
       break;
     case mojom::TtsEventType::ERROR:
       chrome_event_type = TTS_EVENT_ERROR;
       break;
   }
   TtsController::GetInstance()->OnTtsEvent(id, chrome_event_type, char_index,
                                            error_msg);
 }
 
 }  // namespace arc