Introduce a microtask suppression scope and move microtask methods to isolate

src/isolate.cc

 // 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.
 
 #include <stdlib.h>
 
 #include "v8.h"
 
 #include "ast.h"
 #include "bootstrapper.h"
@@ skipping 2234 matching lines @@
   // Fire callbacks.  Increase call depth to prevent recursive callbacks.
   handle_scope_implementer()->IncrementCallDepth();
   if (run_microtasks) Execution::RunMicrotasks(this);
   for (int i = 0; i < call_completed_callbacks_.length(); i++) {
     call_completed_callbacks_.at(i)();
   }
   handle_scope_implementer()->DecrementCallDepth();
 }
 
 
+void Isolate::RunMicrotasks() {
+  if (!microtask_pending())
+    return;
+
+  ASSERT(handle_scope_implementer()->CallDepthIsZero());
+
+  // Increase call depth to prevent recursive callbacks.
+  handle_scope_implementer()->IncrementCallDepth();
+  Execution::RunMicrotasks(this);
+  handle_scope_implementer()->DecrementCallDepth();
+}
+
+
 } }  // namespace v8::internal