[Hotword] Sync Audio History pref every 24 hours, when opening chrome://settings and . . .

chrome/browser/search/hotword_audio_history_handler.h

Index: chrome/browser/search/hotword_audio_history_handler.h
diff --git a/chrome/browser/search/hotword_audio_history_handler.h b/chrome/browser/search/hotword_audio_history_handler.h
index 2f1616b2ff62d59e975cb38f1e0219fb01babca2..13770800249397d5b750427fbc7228dc3363b6b6 100644
--- a/chrome/browser/search/hotword_audio_history_handler.h
+++ b/chrome/browser/search/hotword_audio_history_handler.h
@@ -5,12 +5,17 @@
 #ifndef CHROME_BROWSER_SEARCH_HOTWORD_AUDIO_HISTORY_HANDLER_H_
 #define CHROME_BROWSER_SEARCH_HOTWORD_AUDIO_HISTORY_HANDLER_H_
 
+#include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/prefs/pref_change_registrar.h"
 #include "content/public/browser/browser_context.h"
 
 class Profile;
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace history {
 class WebHistoryService;
 }
@@ -23,12 +28,19 @@ class HotwordAudioHistoryHandler {
   typedef base::Callback<void(bool success, bool new_enabled_value)>
       HotwordAudioHistoryCallback;
 
-  explicit HotwordAudioHistoryHandler(content::BrowserContext* context);
+  HotwordAudioHistoryHandler(
+      content::BrowserContext* context,
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner);
+
   virtual ~HotwordAudioHistoryHandler();
 
+  // Initiates a call to get the updated audio history state.
+  void UpdateAudioHistoryState();
+
   // Updates the current preference value based on the user's account info
   // or false if the user is not signed in.
-  void GetAudioHistoryEnabled(const HotwordAudioHistoryCallback& callback);
+  virtual void GetAudioHistoryEnabled(
+      const HotwordAudioHistoryCallback& callback);
 
   // Sets the user's global pref value for enabling audio history.
   void SetAudioHistoryEnabled(const bool enabled,
@@ -38,6 +50,9 @@ class HotwordAudioHistoryHandler {
   virtual history::WebHistoryService* GetWebHistory();
 
  private:
+  // Helper function used as a callback and to factor out common code.
+  void UpdateLocalPreference(bool success, bool new_enabled_value);
+
   // Called upon completion of web history->GetAudioHistoryEnabled.
   void GetAudioHistoryComplete(
       const HotwordAudioHistoryCallback& callback,
@@ -53,6 +68,8 @@ class HotwordAudioHistoryHandler {
       bool success,
       bool callback_enabled_value);
 
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+
   Profile* profile_;
 
   base::WeakPtrFactory<HotwordAudioHistoryHandler> weak_ptr_factory_;