Change event routers from singletons to being owned by the ExtensionService.

chrome/browser/extensions/extension_bookmarks_module.cc

Index: chrome/browser/extensions/extension_bookmarks_module.cc
diff --git a/chrome/browser/extensions/extension_bookmarks_module.cc b/chrome/browser/extensions/extension_bookmarks_module.cc
index 37a814fcccb0a0d8bc04d3cb06dca8c805e9ea90..08ed2e008e5d196471369255b3e6e3042000c698 100644
--- a/chrome/browser/extensions/extension_bookmarks_module.cc
+++ b/chrome/browser/extensions/extension_bookmarks_module.cc
@@ -117,22 +117,13 @@ void BookmarksFunction::Observe(NotificationType type,
   Release();  // Balanced in Run().
 }
 
-// static
-ExtensionBookmarkEventRouter* ExtensionBookmarkEventRouter::GetInstance() {
-  return Singleton<ExtensionBookmarkEventRouter>::get();
-}
-
-ExtensionBookmarkEventRouter::ExtensionBookmarkEventRouter() {
-}
+ExtensionBookmarkEventRouter::ExtensionBookmarkEventRouter() {}
 
-ExtensionBookmarkEventRouter::~ExtensionBookmarkEventRouter() {
-}
+ExtensionBookmarkEventRouter::~ExtensionBookmarkEventRouter() {}
 
 void ExtensionBookmarkEventRouter::Observe(BookmarkModel* model) {
-  if (models_.find(model) == models_.end()) {
-    model->AddObserver(this);
-    models_.insert(model);
-  }
+  model->AddObserver(this);
+  model_ = model;
 }
 
 void ExtensionBookmarkEventRouter::DispatchEvent(Profile *profile,