Add API support for passing a C++ function as a microtask callback

src/isolate.h

 // 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.
 
 #ifndef V8_ISOLATE_H_
 #define V8_ISOLATE_H_
 
 #include "../include/v8-debug.h"
 #include "allocation.h"
 #include "assert-scope.h"
@@ skipping 1059 matching lines @@
     return id;
   }
 
   // Get (and lazily initialize) the registry for per-isolate symbols.
   Handle<JSObject> GetSymbolRegistry();
 
   void AddCallCompletedCallback(CallCompletedCallback callback);
   void RemoveCallCompletedCallback(CallCompletedCallback callback);
   void FireCallCompletedCallback();
 
-  void EnqueueMicrotask(Handle<JSFunction> microtask);
+  void EnqueueMicrotask(Handle<Object> microtask);
   void RunMicrotasks();
 
  private:
   Isolate();
 
   friend struct GlobalState;
   friend struct InitializeGlobalState;
 
   enum State {
     UNINITIALIZED,    // Some components may not have been allocated.
@@ skipping 398 matching lines @@
   }
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_H_