Add thread affinity and ASSERT() for same-thread restriction to WTF::Function

third_party/WebKit/Source/platform/threading/BackgroundTaskRunner.cpp

Index: third_party/WebKit/Source/platform/threading/BackgroundTaskRunner.cpp
diff --git a/third_party/WebKit/Source/platform/threading/BackgroundTaskRunner.cpp b/third_party/WebKit/Source/platform/threading/BackgroundTaskRunner.cpp
index 8a757d43939e37c12168300c8cb3ca0495b75903..c75e7e8302daeffc9e4c27cf163c493988d3229b 100644
--- a/third_party/WebKit/Source/platform/threading/BackgroundTaskRunner.cpp
+++ b/third_party/WebKit/Source/platform/threading/BackgroundTaskRunner.cpp
@@ -11,12 +11,12 @@
 
 namespace blink {
 
-static void RunBackgroundTask(PassOwnPtr<Closure> closure)
+static void RunBackgroundTask(PassOwnPtr<CrossThreadClosure> closure)
 {
     (*closure)();
 }
 
-void BackgroundTaskRunner::postOnBackgroundThread(const WebTraceLocation& location, PassOwnPtr<Closure> closure, TaskSize taskSize)
+void BackgroundTaskRunner::postOnBackgroundThread(const WebTraceLocation& location, PassOwnPtr<CrossThreadClosure> closure, TaskSize taskSize)
 {
     tracked_objects::Location baseLocation(location.functionName(), location.fileName(), 0, nullptr);
     base::WorkerPool::PostTask(baseLocation, base::Bind(&RunBackgroundTask, closure), taskSize == TaskSizeLongRunningTask);