Make sure that there is enough time left before finishing incremental marking in idle notification.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index 587b67bdf064c771de14f9b08bb9d839773c5b56..6f5d70982097db39add6dea0fc1e43df928b5919 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -1090,7 +1090,7 @@ class Heap {
   void DisableInlineAllocation();
 
   // Implements the corresponding V8 API function.
-  bool IdleNotification(int hint);
+  bool IdleNotification(int idle_time_in_ms);
 
   // Declare all the root indices.  This defines the root list order.
   enum RootListIndex {
@@ -2063,7 +2063,10 @@ class Heap {
     return heap_size_mb / kMbPerMs;
   }
 
-  void AdvanceIdleIncrementalMarking(intptr_t step_size);
+  // Returns the time in ms spent in incremental marking.
+  int AdvanceIdleIncrementalMarking(intptr_t step_size);
+
+  void FinalizeIdleIncrementalMarking();
 
   void ClearObjectStats(bool clear_last_time_stats = false);