Introduce debug events for Microtask queue.

src/debug-debugger.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Default number of frames to include in the response to backtrace request.
 var kDefaultBacktraceLength = 10;
 
 var Debug = {};
 
 // Regular expression to skip "crud" at the beginning of a source line which is
 // not really code. Currently the regular expression matches whitespace and
 // comments.
 var sourceLineBeginningSkip = /^(?:\s*(?:\/\*.*?\*\/)*)*/;
 
 // Debug events which can occour in the V8 JavaScript engine. These originate
 // from the API include file debug.h.
 Debug.DebugEvent = { Break: 1,
                      Exception: 2,
                      NewFunction: 3,
                      BeforeCompile: 4,
                      AfterCompile: 5,
                      CompileError: 6,
-                     PromiseEvent: 7 };
+                     PromiseEvent: 7,
+                     AsyncTaskEvent: 8 };
 
 // Types of exceptions that can be broken upon.
 Debug.ExceptionBreak = { Caught : 0,
                          Uncaught: 1 };
 
 // The different types of steps.
 Debug.StepAction = { StepOut: 0,
                      StepNext: 1,
                      StepIn: 2,
                      StepMin: 3,
@@ skipping 1185 matching lines @@
 
 
 NewPromiseEvent.prototype.promise = PromiseGetter;
 
 
 NewPromiseEvent.prototype.resolver = function() {
   return MakeMirror(this.resolver_);
 }
 
 
+function MakeAsyncTaskEvent(event_data) {
+  return new AsyncTaskEvent(event_data);
+}
+
+
+function AsyncTaskEvent(event_data) {
+  this.type_ = event_data.type;
+  this.name_ = event_data.name;
+  this.id_ = event_data.id;
+}
+
+
+AsyncTaskEvent.prototype.type = function() {
+  return this.type_;
+}
+
+
+AsyncTaskEvent.prototype.name = function() {
+  return this.name_;
+}
+
+
+AsyncTaskEvent.prototype.id = function() {
+  return this.id_;
+}
+
+
 function DebugCommandProcessor(exec_state, opt_is_running) {
   this.exec_state_ = exec_state;
   this.running_ = opt_is_running || false;
 }
 
 
 DebugCommandProcessor.prototype.processDebugRequest = function (request) {
   return this.processDebugJSONRequest(request);
 };
 
@@ skipping 1301 matching lines @@
 
     default:
       json = null;
   }
   return json;
 }
 
 Debug.TestApi = {
   CommandProcessorResolveValue: DebugCommandProcessor.resolveValue_
 };