Use idle task to perform incremental marking steps.

src/v8.h

 // Copyright 2011 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.
 
 //
 // Top include for all V8 .cc files.
 //
 
 #ifndef V8_V8_H_
 #define V8_V8_H_
@@ skipping 54 matching lines @@
   static void SetEntropySource(EntropySource source);
   // Support for return-address rewriting profilers.
   static void SetReturnAddressLocationResolver(
       ReturnAddressLocationResolver resolver);
   // Support for entry hooking JITed code.
   static void SetFunctionEntryHook(FunctionEntryHook entry_hook);
 
   static void InitializePlatform(v8::Platform* platform);
   static void ShutdownPlatform();
   static v8::Platform* GetCurrentPlatform();
+  // Replaces the current platform with the given platform.
+  // Should be used only for testing.
+  static void SetPlatformForTesting(v8::Platform* platform);
 
   static void SetNativesBlob(StartupData* natives_blob);
   static void SetSnapshotBlob(StartupData* snapshot_blob);
 
  private:
   static void InitializeOncePerProcessImpl();
   static void InitializeOncePerProcess();
 
   // v8::Platform to use.
   static v8::Platform* platform_;
 };
 
 
 // JavaScript defines two kinds of 'nil'.
 enum NilValue { kNullValue, kUndefinedValue };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_V8_H_