Only return the visible page actions from PageActionController.

chrome/browser/extensions/extension_tab_helper.cc

Index: chrome/browser/extensions/extension_tab_helper.cc
diff --git a/chrome/browser/extensions/extension_tab_helper.cc b/chrome/browser/extensions/extension_tab_helper.cc
index ce76ddcc08d958c87787e4ee543376a81770be61..ffdac6bb7b491e8761880c72055d2da67d1df103 100644
--- a/chrome/browser/extensions/extension_tab_helper.cc
+++ b/chrome/browser/extensions/extension_tab_helper.cc
@@ -52,14 +52,26 @@ void ExtensionTabHelper::CopyStateFrom(const ExtensionTabHelper& source) {
 }
 
 void ExtensionTabHelper::PageActionStateChanged() {
+  // TODO(kalman): replace this with just the Observer interface.
   web_contents()->NotifyNavigationStateChanged(
       content::INVALIDATE_TYPE_PAGE_ACTIONS);
+
+  FOR_EACH_OBSERVER(Observer, observers_, OnPageActionStateChanged());
 }
 
 void ExtensionTabHelper::GetApplicationInfo(int32 page_id) {
   Send(new ExtensionMsg_GetApplicationInfo(routing_id(), page_id));
 }
 
+void ExtensionTabHelper::AddObserver(ExtensionTabHelper::Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void ExtensionTabHelper::RemoveObserver(
+    ExtensionTabHelper::Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
 void ExtensionTabHelper::SetExtensionApp(const Extension* extension) {
   DCHECK(!extension || extension->GetFullLaunchURL().is_valid());
   extension_app_ = extension;