Start incremental marking on idle notification.

src/incremental-marking.cc

Index: src/incremental-marking.cc
diff --git a/src/incremental-marking.cc b/src/incremental-marking.cc
index bd0f0837b0bd5860d91d38fb8c890622db86bb02..987abe4564970cca6d23e070704317d625fc874e 100644
--- a/src/incremental-marking.cc
+++ b/src/incremental-marking.cc
@@ -744,7 +744,9 @@ void IncrementalMarking::MarkingComplete() {
   if (FLAG_trace_incremental_marking) {
     PrintF("[IncrementalMarking] Complete (normal).\n");
   }
-  heap_->isolate()->stack_guard()->RequestGC();
+  if (!heap_->idle_notification_will_schedule_next_gc()) {
+    heap_->isolate()->stack_guard()->RequestGC();
+  }
 }
 
 
@@ -772,8 +774,7 @@ void IncrementalMarking::Step(intptr_t allocated_bytes) {
   }
 
   if (state_ == SWEEPING) {
-    if (heap_->old_pointer_space()->AdvanceSweeper(bytes_to_process) &&
-        heap_->old_data_space()->AdvanceSweeper(bytes_to_process)) {
+    if (heap_->AdvanceSweepers(bytes_to_process)) {
       bytes_scanned_ = 0;
       StartMarking(PREVENT_COMPACTION);
     }