Change many extension event routers to not be singletons and to be more profile-aware.

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 e325aa01dbc879290259e28750aa531675578b17..3b204c35f4014ffa8773c07e3063f1ca60a5d74d 100644
--- a/chrome/browser/extensions/extension_bookmarks_module.cc
+++ b/chrome/browser/extensions/extension_bookmarks_module.cc
@@ -118,11 +118,6 @@ void BookmarksFunction::Observe(NotificationType type,
   Release();  // Balanced in Run().
 }
 
-// static
-ExtensionBookmarkEventRouter* ExtensionBookmarkEventRouter::GetInstance() {
-  return Singleton<ExtensionBookmarkEventRouter>::get();
-}
-
 ExtensionBookmarkEventRouter::ExtensionBookmarkEventRouter() {
 }
 
@@ -130,10 +125,7 @@ ExtensionBookmarkEventRouter::~ExtensionBookmarkEventRouter() {
 }
 
 void ExtensionBookmarkEventRouter::Observe(BookmarkModel* model) {
-  if (models_.find(model) == models_.end()) {
-    model->AddObserver(this);
-    models_.insert(model);
-  }
+  model->AddObserver(this);

[asargent_no_longer_on_chrome, 2011/06/23 22:18:38]

Is there a matching call to RemoveObserver somewhere? I expected to see it in
here somewhere.

[Yoyo Zhou, 2011/06/24 17:21:38]

There wasn't before... we should probably have one assuming the model hasn't
been destroyed by the time the router is destroyed. Can we count on that?

[asargent_no_longer_on_chrome, 2011/06/24 18:56:39]

Looks like BookmarkModelObserver's get their BookmarkModelBeingDeleted method
called when the model is being destructed, so we can just implement that and
drop our ptr to the model then, and skip calling RemoveObserver in our own
destructor here if the ptr is NULL. 

[Yoyo Zhou, 2011/06/24 22:10:33]

We don't keep a pointer to the model anymore; I guess we would have to to use it
in our own destructor.

Both the ExtensionService and BookmarkModel are scoped_ptrs held by the Profile,
so they would get destroyed at approximately the same time.

 }
 
 void ExtensionBookmarkEventRouter::DispatchEvent(Profile *profile,