Revert of Implement async AbortAll for the compiler dispatcher

src/cancelable-task.cc

Index: src/cancelable-task.cc
diff --git a/src/cancelable-task.cc b/src/cancelable-task.cc
index b0387f4dc05b55f4345bd415ab334e9e72f94651..b712d98877ce930946bd8ceb4754bf4fe403ef8f 100644
--- a/src/cancelable-task.cc
+++ b/src/cancelable-task.cc
@@ -93,24 +93,6 @@
   }
 }
 
-CancelableTaskManager::TryAbortResult CancelableTaskManager::TryAbortAll() {
-  // Clean up all cancelable fore- and background tasks. Tasks are canceled on
-  // the way if possible, i.e., if they have not started yet.
-  base::LockGuard<base::Mutex> guard(&mutex_);
-
-  if (cancelable_tasks_.empty()) return kTaskRemoved;
-
-  for (auto it = cancelable_tasks_.begin(); it != cancelable_tasks_.end();) {
-    if (it->second->Cancel()) {
-      it = cancelable_tasks_.erase(it);
-    } else {
-      ++it;
-    }
-  }
-
-  return cancelable_tasks_.empty() ? kTaskAborted : kTaskRunning;
-}
-
 CancelableTask::CancelableTask(Isolate* isolate)
     : CancelableTask(isolate, isolate->cancelable_task_manager()) {}