1 files changed, 14 insertions, 0 deletions
diff --git a/components/ui/zoom/zoom_event_manager.h b/components/ui/zoom/zoom_event_manager.h
index 3f0fcf0..72d335d 100644
--- a/components/ui/zoom/zoom_event_manager.h
+++ b/components/ui/zoom/zoom_event_manager.h
@@ -7,6 +7,7 @@
 
 #include "base/callback_list.h"
 #include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
 #include "base/supports_user_data.h"
 #include "content/public/browser/host_zoom_map.h"
 
@@ -16,6 +17,8 @@ class BrowserContext;
 
 namespace ui_zoom {
 
+class ZoomEventManagerObserver;
+
 // This class serves as a target for event notifications from all ZoomController
 // objects. Classes that need to know about browser-specific zoom events (e.g.
 // manual-mode zoom) should subscribe here.
@@ -34,9 +37,19 @@ class ZoomEventManager : public base::SupportsUserData::Data {
   void OnZoomLevelChanged(const content::HostZoomMap::ZoomLevelChange& change);
 
   // Add and remove zoom level changed callbacks.
+  // TODO(wjmaclean): Convert this callback mechanism to use
+  // ZoomEventManagerObserver instead.
   scoped_ptr<content::HostZoomMap::Subscription> AddZoomLevelChangedCallback(
       const content::HostZoomMap::ZoomLevelChangedCallback& callback);
 
+  // Called by ZoomLevelDelegates when changes are made to the default zoom
+  // level for their associated HostZoomMap.
+  void OnDefaultZoomLevelChanged();
+
+  // Add and remove observers.
+  void AddZoomEventManagerObserver(ZoomEventManagerObserver* observer);
+  void RemoveZoomEventManagerObserver(ZoomEventManagerObserver* observer);
+
   // Get a weak ptr to be used by clients who may themselves be UserData for
   // the context, since the order of destruction is undefined between the client
   // and this class.
@@ -47,6 +60,7 @@ class ZoomEventManager : public base::SupportsUserData::Data {
  private:
   base::CallbackList<void(const content::HostZoomMap::ZoomLevelChange&)>
       zoom_level_changed_callbacks_;
+  ObserverList<ZoomEventManagerObserver> observers_;
   base::WeakPtrFactory<ZoomEventManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ZoomEventManager);