Introduce debug events for Microtask queue.

include/v8-debug.h

 // Copyright 2008 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.
 
 #ifndef V8_V8_DEBUG_H_
 #define V8_V8_DEBUG_H_
 
 #include "v8.h"
 
 /**
  * Debugger support for the V8 JavaScript engine.
  */
 namespace v8 {
 
 // Debug events which can occur in the V8 JavaScript engine.
 enum DebugEvent {
   Break = 1,
   Exception = 2,
   NewFunction = 3,
   BeforeCompile = 4,
   AfterCompile  = 5,
   CompileError = 6,
   PromiseEvent = 7,
-  BreakForCommand = 8
+  AsyncTaskEvent = 8,
+  BreakForCommand = 9
 };
 
 
 class V8_EXPORT Debug {
  public:
   /**
    * A client object passed to the v8 debugger whose ownership will be taken by
    * it. v8 is always responsible for deleting the object.
    */
   class ClientData {
@@ skipping 222 matching lines @@
 };
 
 
 }  // namespace v8
 
 
 #undef EXPORT
 
 
 #endif  // V8_V8_DEBUG_H_