Use the regular start incremental marking strategy in the idle notification.

src/heap/incremental-marking.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_HEAP_INCREMENTAL_MARKING_H_
 #define V8_HEAP_INCREMENTAL_MARKING_H_
 
 
 #include "src/execution.h"
 #include "src/heap/mark-compact.h"
@@ skipping 26 matching lines @@
   inline bool IsStopped() { return state() == STOPPED; }
 
   INLINE(bool IsMarking()) { return state() >= MARKING; }
 
   inline bool IsMarkingIncomplete() { return state() == MARKING; }
 
   inline bool IsComplete() { return state() == COMPLETE; }
 
   bool WorthActivating();
 
+  bool ShouldActivate();
+
   enum CompactionFlag { ALLOW_COMPACTION, PREVENT_COMPACTION };
 
   void Start(CompactionFlag flag = ALLOW_COMPACTION);
 
   void Stop();
 
   void PrepareForScavenge();
 
   void UpdateMarkingDequeAfterScavenge();
 
@@ skipping 158 matching lines @@
   int no_marking_scope_depth_;
 
   int unscanned_bytes_of_large_object_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(IncrementalMarking);
 };
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_INCREMENTAL_MARKING_H_