Support onvoiceschanged for extension-based tts engines.

chrome/browser/speech/tts_controller.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/tts_controller.h"
 
 #include <string>
 #include <vector>
 
 #include "base/float_util.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/speech/extension_api/tts_engine_extension_api.h"
 #include "chrome/browser/speech/extension_api/tts_extension_api.h"
+#include "chrome/browser/speech/tts_engine_extension_observer.h"
+#include "chrome/browser/speech/tts_engine_extension_observer.h"
 #include "chrome/browser/speech/tts_platform.h"
 #include "chrome/common/extensions/api/speech/tts_engine_manifest_handler.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/common/extension.h"
 
 namespace {
 // A value to be used to indicate that there is no char index available.
 const int kInvalidCharIndex = -1;
 
 // Given a language/region code of the form 'fr-FR', returns just the basic
@@ skipping 123 matching lines @@
     SpeakNow(utterance);
   }
 }
 
 void TtsController::SpeakNow(Utterance* utterance) {
   // Ensure we have all built-in voices loaded. This is a no-op if already
   // loaded.
   bool loaded_built_in =
       GetPlatformImpl()->LoadBuiltInTtsExtension(utterance->profile());
 
+  // Ensure we're observing newly added engines for the given profile.
+  TtsEngineExtensionObserver::GetInstance(utterance->profile());

[dmazzoni, 2014/07/07 15:37:26]

Is there a better place for this?

1) It feels like we should try to do this on more than just "Speak"

2) We're trying to move TtsController into content so I'd like to eliminate
direct dependencies on extension-related code. Can this be abstracted?

[David Tseng, 2014/07/08 23:43:31]

I've moved this call. Should address some of your other concerns I think. Let me
know if that looks like a good change and I think I can then clean up the
observer class a bit more (e.g. no longer a service).

+
   // Get all available voices and try to find a matching voice.
   std::vector<VoiceData> voices;
   GetVoices(utterance->profile(), &voices);
   int index = GetMatchingVoice(utterance, voices);
 
   VoiceData voice;
   if (index != -1) {
     // Select the matching voice.
     voice = voices[index];
   } else {
@@ skipping 269 matching lines @@
 }
 
 void TtsController::AddVoicesChangedDelegate(VoicesChangedDelegate* delegate) {
   voices_changed_delegates_.insert(delegate);
 }
 
 void TtsController::RemoveVoicesChangedDelegate(
     VoicesChangedDelegate* delegate) {
   voices_changed_delegates_.erase(delegate);
 }