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

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

Index: third_party/WebKit/Source/modules/budget/NavigatorBudget.idl
diff --git a/third_party/WebKit/Source/modules/budget/NavigatorBudget.idl b/third_party/WebKit/Source/modules/budget/NavigatorBudget.idl
index 2ca09c05bf2c90cfaa5b4044e1f234676acb8fdb..1462027432bee3c9257b04d8989258ec2a93a27b 100644
--- a/third_party/WebKit/Source/modules/budget/NavigatorBudget.idl
+++ b/third_party/WebKit/Source/modules/budget/NavigatorBudget.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.
 
-// https://wicg.github.io/budget-api/#navigator-budget-interface
+// https://wicg.github.io/budget-api/#navigator-workernavigator-extensions
 
 [
     RuntimeEnabled=Budget
 ] partial interface Navigator {
-    // TODO(harkness): In the spec, this is not a partial interface.
-    readonly attribute BudgetService budget;
+    [SameObject] readonly attribute BudgetService budget;
 };