Change the return type of WTF::bind() to |OwnPtr<Function>|

Source/platform/scheduler/Scheduler.h

Index: Source/platform/scheduler/Scheduler.h
diff --git a/Source/platform/scheduler/Scheduler.h b/Source/platform/scheduler/Scheduler.h
index 62b08a69f0f1098aa97ad97e13f2f57f9e48767a..89449d04158d2412a6ec31cabd17af05312edc6d 100644
--- a/Source/platform/scheduler/Scheduler.h
+++ b/Source/platform/scheduler/Scheduler.h
@@ -27,7 +27,7 @@ public:
 
     // For non-critical tasks which may be reordered relative to other task types and may be starved
     // for an arbitrarily long time if no idle time is available.
-    void postIdleTask(const TraceLocation&, const IdleTask&);
+    void postIdleTask(const TraceLocation&, PassOwnPtr<IdleTask>);
 
     // Returns true if there is high priority work pending on the main thread
     // and the caller should yield to let the scheduler service that work.