Add CancelableIdleTask.

src/cancelable-task.cc

Index: src/cancelable-task.cc
diff --git a/src/cancelable-task.cc b/src/cancelable-task.cc
index 5eab9605b4a3c692b6ce58dd4ce51a148e7bd072..32d5057c49ead4149d9487e91a12cf8cdd304cd0 100644
--- a/src/cancelable-task.cc
+++ b/src/cancelable-task.cc
@@ -11,13 +11,13 @@ namespace v8 {
 namespace internal {
 
 
-CancelableTask::CancelableTask(Isolate* isolate)
+Cancelable::Cancelable(Isolate* isolate)
     : isolate_(isolate), is_cancelled_(false) {
   isolate->RegisterCancelableTask(this);
 }
 
 
-CancelableTask::~CancelableTask() {
+Cancelable::~Cancelable() {
   if (!is_cancelled_) {
     isolate_->RemoveCancelableTask(this);
   }