Hook up over approximating the weak closure to the idle time handler

src/heap/gc-idle-time-handler.cc

Index: src/heap/gc-idle-time-handler.cc
diff --git a/src/heap/gc-idle-time-handler.cc b/src/heap/gc-idle-time-handler.cc
index ff2a559dd539dae2dc3ce3b1c09477243ba6f704..a1c9c7f23225a96280c98f914934c033146417ae 100644
--- a/src/heap/gc-idle-time-handler.cc
+++ b/src/heap/gc-idle-time-handler.cc
@@ -16,6 +16,7 @@ const size_t GCIdleTimeHandler::kMinTimeForFinalizeSweeping = 100;
 const int GCIdleTimeHandler::kMaxMarkCompactsInIdleRound = 7;
 const int GCIdleTimeHandler::kIdleScavengeThreshold = 5;
 const double GCIdleTimeHandler::kHighContextDisposalRate = 100;
+const size_t GCIdleTimeHandler::kMinTimeForOverApproximatingWeakClosureInMs = 1;
 
 
 void GCIdleTimeAction::Print() {
@@ -176,6 +177,13 @@ bool GCIdleTimeHandler::ShouldDoFinalIncrementalMarkCompact(
 }
 
 
+bool GCIdleTimeHandler::ShouldDoOverApproximateWeakClosure(
+    size_t idle_time_in_ms) {
+  // TODO(jochen): Estimate the time it will take to build the object groups.
+  return idle_time_in_ms >= kMinTimeForOverApproximatingWeakClosureInMs;
+}
+
+
 // The following logic is implemented by the controller:
 // (1) If we don't have any idle time, do nothing, unless a context was
 // disposed, incremental marking is stopped, and the heap is small. Then do