Add new extension APIs related to animation policy.

chrome/browser/extensions/api/preference/preference_api.h

Index: chrome/browser/extensions/api/preference/preference_api.h
diff --git a/chrome/browser/extensions/api/preference/preference_api.h b/chrome/browser/extensions/api/preference/preference_api.h
index 0f95a9be60ce7dd24d4b0366bdf66c439ec14535..51b29312bb24ed6a4fcec7966c2120e0dd0ab0a0 100644
--- a/chrome/browser/extensions/api/preference/preference_api.h
+++ b/chrome/browser/extensions/api/preference/preference_api.h
@@ -110,6 +110,8 @@ class PreferenceAPI : public PreferenceAPIBase,
   // EventRouter::Observer implementation.
   void OnListenerAdded(const EventListenerInfo& details) override;
 
+  void UpdateAnimationPolicy();
+
  private:
   friend class BrowserContextKeyedAPIFactory<PreferenceAPI>;
 
@@ -126,6 +128,7 @@ class PreferenceAPI : public PreferenceAPIBase,
   scoped_refptr<ContentSettingsStore> content_settings_store() override;
 
   Profile* profile_;
+  PrefChangeRegistrar pref_change_registrar_;
 
   // BrowserContextKeyedAPI implementation.
   static const char* service_name() {