[Sync] Refactor non-frontend DTC to handle new API properly.

chrome/browser/extensions/extension_service.h

Index: chrome/browser/extensions/extension_service.h
diff --git a/chrome/browser/extensions/extension_service.h b/chrome/browser/extensions/extension_service.h
index f30c480a3ba4fda680197b911e31b34a319423ed..ad5b80f2de504870124f064f71fa90fafe4016ea 100644
--- a/chrome/browser/extensions/extension_service.h
+++ b/chrome/browser/extensions/extension_service.h
@@ -75,7 +75,9 @@ class ExtensionInputMethodEventRouter;
 
 // This is an interface class to encapsulate the dependencies that
 // various classes have on ExtensionService. This allows easy mocking.
-class ExtensionServiceInterface : public SyncableService {
+class ExtensionServiceInterface
+    : public SyncableService,
+      public base::SupportsWeakPtr<ExtensionServiceInterface> {

[akalin, 2011/10/12 19:54:21]

can you stick this onto the actual ExtensionService class?  Actually, it may
already support weak pointers; I'm pretty sure it at least has a WeakPtrFactory.

You may want to do the "make every syncableservice inherit from SupportsWeakPtr"
thing as a separate CL, as it may involve other OWNERS, and this CL is pretty
big already.

[Nicolas Zea, 2011/10/12 23:47:43]

Discussed offline. Sticking with SyncableService implementing the weakptr for
now, with a TODO to transition to the services themselves implementing it.

  public:
   // A function that returns true if the given extension should be
   // included and false if it should be filtered out.  Identical to