Remove all but one use of WeakPtrFactory::DetachFromThread.

win8/test/ui_automation_client.cc

Index: win8/test/ui_automation_client.cc
diff --git a/win8/test/ui_automation_client.cc b/win8/test/ui_automation_client.cc
index 8c8663083b9b85f3af3a8088c65c0506ce5ed353..ef742f20fecd2fe4cccb11c912e2182b5fe5909d 100644
--- a/win8/test/ui_automation_client.cc
+++ b/win8/test/ui_automation_client.cc
@@ -158,11 +158,7 @@ HRESULT UIAutomationClient::Context::EventHandler::HandleAutomationEvent(
 base::WeakPtr<UIAutomationClient::Context>
     UIAutomationClient::Context::Create() {
   Context* context = new Context();
-  base::WeakPtr<Context> context_ptr(context->weak_ptr_factory_.GetWeakPtr());
-  // Unbind from this thread so that the instance will bind to the automation
-  // thread when Initialize is called.
-  context->weak_ptr_factory_.DetachFromThread();
-  return context_ptr;
+  return context->weak_ptr_factory_.GetWeakPtr();
 }
 
 void UIAutomationClient::Context::DeleteOnAutomationThread() {