Automatically trigger installation of high-quality speech synthesis extension.

chrome/browser/speech/tts_chromeos.cc

Index: chrome/browser/speech/tts_chromeos.cc
diff --git a/chrome/browser/speech/tts_chromeos.cc b/chrome/browser/speech/tts_chromeos.cc
index e42cb0c546b4642050ddd73fc9df48d3ef7dd4fd..1c86c5642cc2d308bc89a19b5f0acff80638921b 100644
--- a/chrome/browser/speech/tts_chromeos.cc
+++ b/chrome/browser/speech/tts_chromeos.cc
@@ -2,13 +2,27 @@
 // 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_extension_loader_chromeos.h"
+#include "base/bind_helpers.h"
+#include "base/logging.h"
+#include "base/prefs/scoped_user_pref_update.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/speech/tts_platform.h"
+#include "chrome/common/extensions/extension_constants.h"
+#include "chrome/common/pref_names.h"
+
+namespace {
+
+// Trigger installing high-quality speech after this many utterances
+// have been spoken in one session.
+const int kHighQualitySpeechUtteranceThreshold = 100;
+
+}  // anonymous namespace
 
 // Chrome OS doesn't have native TTS, instead it includes a built-in
-// component extension that provides speech synthesis. This class includes
-// an implementation of LoadBuiltInTtsExtension and dummy implementations of
-// everything else.
+// component extension that provides speech synthesis. This class monitors
+// use of this component extension and triggers installing a higher-quality
+// speech synthesis extension if a certain number of utterances are spoken
+// in a single session.
 class TtsPlatformImplChromeOs
     : public TtsPlatformImpl {
  public:
@@ -17,10 +31,6 @@ class TtsPlatformImplChromeOs
     return false;
   }
 
-  virtual bool LoadBuiltInTtsExtension(Profile* profile) OVERRIDE {
-    return TtsExtensionLoaderChromeOs::GetInstance(profile)->LoadTtsExtension();
-  }
-
   virtual bool Speak(
       int utterance_id,
       const std::string& utterance,
@@ -30,33 +40,63 @@ class TtsPlatformImplChromeOs
     return false;
   }
 
-  virtual bool StopSpeaking() OVERRIDE {
-    return false;
-  }
-
+  virtual bool StopSpeaking() OVERRIDE { return false; }
   virtual void Pause() OVERRIDE {}
-
   virtual void Resume() OVERRIDE {}
+  virtual bool IsSpeaking() OVERRIDE { return false; }
+  virtual void GetVoices(std::vector<VoiceData>* out_voices) OVERRIDE {}
 
-  virtual bool IsSpeaking() OVERRIDE {
-    return false;
-  }
-
-  virtual void GetVoices(std::vector<VoiceData>* out_voices) OVERRIDE {
-  }
+  virtual void WillSpeakUtteranceWithVoice(
+      const Utterance* utterance,
+      const VoiceData& voice_data) OVERRIDE;
 
   // Get the single instance of this class.
   static TtsPlatformImplChromeOs* GetInstance();
 
  private:
-  TtsPlatformImplChromeOs() {}
+  TtsPlatformImplChromeOs();
   virtual ~TtsPlatformImplChromeOs() {}
 
   friend struct DefaultSingletonTraits<TtsPlatformImplChromeOs>;
 
+  // A count of the number of utterances spoken for each language
+  // using the built-in speech synthesis. When enough utterances have
+  // been spoken in a single session, automatically enable install
+  // the high-quality speech synthesis extension for that language.
+  base::hash_map<std::string, int> lang_utterance_count_;
+
   DISALLOW_COPY_AND_ASSIGN(TtsPlatformImplChromeOs);
 };
 
+TtsPlatformImplChromeOs::TtsPlatformImplChromeOs() {
+}
+
+void TtsPlatformImplChromeOs::WillSpeakUtteranceWithVoice(
+    const Utterance* utterance,
+    const VoiceData& voice_data) {
+  CHECK(utterance);
+  CHECK(utterance->profile());
+
+  if (utterance->profile()->IsOffTheRecord())
+    return;
+
+  if (voice_data.extension_id != extension_misc::kSpeechSynthesisExtensionId)
+    return;
+
+  lang_utterance_count_[voice_data.lang]++;
+  if (lang_utterance_count_[voice_data.lang] !=
+          kHighQualitySpeechUtteranceThreshold) {
+    return;
+  }
+
+  // Add this language to the list that are allowed to install a
+  // component extension for high-quality speech synthesis, overriding
+  // the lower-quality one.
+  ListPrefUpdate updater(utterance->profile()->GetPrefs(),
+                         prefs::kHighQualitySpeechSynthesisLanguages);
+  updater->AppendIfNotPresent(new base::StringValue(voice_data.lang));
+}
+
 // static
 TtsPlatformImpl* TtsPlatformImpl::GetInstance() {
   return TtsPlatformImplChromeOs::GetInstance();