Add [SameObject] to bring the Budget API in syn with the proposed spec.

third_party/WebKit/Source/modules/budget/WorkerNavigatorBudget.idl

Index: third_party/WebKit/Source/modules/budget/WorkerNavigatorBudget.idl
diff --git a/third_party/WebKit/Source/modules/budget/WorkerNavigatorBudget.idl b/third_party/WebKit/Source/modules/budget/WorkerNavigatorBudget.idl
index 5a88538dfebffd4d64d1e2926f3e3301897c24d2..9720c9730ae764706aa904ad541f7128d3c39cfa 100644
--- a/third_party/WebKit/Source/modules/budget/WorkerNavigatorBudget.idl
+++ b/third_party/WebKit/Source/modules/budget/WorkerNavigatorBudget.idl
@@ -2,11 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// TODO(harkness): Update to WorkerNavigator partial interface documentation.
-// https://wicg.github.io/budget-api/#navigator-budget-interface
+// https://wicg.github.io/budget-api/#navigator-workernavigator-extensions
 
 [
     RuntimeEnabled=Budget
 ] partial interface WorkerNavigator {
-    readonly attribute BudgetService budget;
+    [SameObject] readonly attribute BudgetService budget;
 };