Reland "[heap] Uncommit marking deque in concurrent task."

src/cancelable-task.h

Index: src/cancelable-task.h
diff --git a/src/cancelable-task.h b/src/cancelable-task.h
index 9f17bfb9a7326d15b171aa75322d04008b656b09..65f98e766287dea41bb89ec2f1e02cdc65242df4 100644
--- a/src/cancelable-task.h
+++ b/src/cancelable-task.h
@@ -32,14 +32,14 @@ class V8_EXPORT_PRIVATE CancelableTaskManager {
   uint32_t Register(Cancelable* task);
 
   // Try to abort running a task identified by {id}. The possible outcomes are:
-  // (1) The task is already finished running and thus has been removed from
-  //     the manager.
+  // (1) The task is already finished running or was canceled before and
+  //     thus has been removed from the manager.
   // (2) The task is currently running and cannot be canceled anymore.
   // (3) The task is not yet running (or finished) so it is canceled and
   //     removed.
   //
-  // Returns {false} for (1) and (2), and {true} for (3).
-  bool TryAbort(uint32_t id);
+  enum TryAbortResult { kTaskRemoved, kTaskRunning, kTaskAborted };
+  TryAbortResult TryAbort(uint32_t id);
 
   // Cancels all remaining registered tasks and waits for tasks that are
   // already running. This disallows subsequent Register calls.