Use idle task to perform incremental marking steps.

src/v8.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 "src/v8.h"
 
 #include "src/assembler.h"
 #include "src/base/once.h"
 #include "src/base/platform/platform.h"
 #include "src/bootstrapper.h"
@@ skipping 108 matching lines @@
   platform_ = NULL;
 }
 
 
 v8::Platform* V8::GetCurrentPlatform() {
   DCHECK(platform_);
   return platform_;
 }
 
 
+void V8::SetPlatformForTesting(v8::Platform* platform) { platform_ = platform; }
+
+
 void V8::SetNativesBlob(StartupData* natives_blob) {
 #ifdef V8_USE_EXTERNAL_STARTUP_DATA
   base::CallOnce(&init_natives_once, &SetNativesFromFile, natives_blob);
 #else
   CHECK(false);
 #endif
 }
 
 
 void V8::SetSnapshotBlob(StartupData* snapshot_blob) {
 #ifdef V8_USE_EXTERNAL_STARTUP_DATA
   base::CallOnce(&init_snapshot_once, &SetSnapshotFromFile, snapshot_blob);
 #else
   CHECK(false);
 #endif
 }
 }  // namespace internal
 }  // namespace v8