Perform full GC in background idle notification.

src/heap/memory-reducer.cc

Index: src/heap/memory-reducer.cc
diff --git a/src/heap/memory-reducer.cc b/src/heap/memory-reducer.cc
index 7063fc4b2eb5c549ad6c1ba26e350461a4c824da..8686b7d4ccbebab87ac5cf089fdee78887b8d566 100644
--- a/src/heap/memory-reducer.cc
+++ b/src/heap/memory-reducer.cc
@@ -95,14 +95,8 @@ void MemoryReducer::NotifyBackgroundIdleNotification(const Event& event) {
   if (old_action == kWait && state_.action == kWait &&
       old_started_gcs + 1 == state_.started_gcs) {
     DCHECK(heap()->incremental_marking()->IsStopped());
-    DCHECK(FLAG_incremental_marking);
-    heap()->StartIdleIncrementalMarking();
-    if (FLAG_trace_gc_verbose) {
-      PrintIsolate(heap()->isolate(),
-                   "Memory reducer: started GC #%d"
-                   " (background idle)\n",
-                   state_.started_gcs);
-    }
+    heap()->CollectAllGarbage(Heap::kReduceMemoryFootprintMask,

[Hannes Payer (out of office), 2015/08/03 19:11:39]

Let's leave a comment here why we do a full GCs. Or actually a TODO, it may be
beneficial to incremental marking here.

[ulan, 2015/08/04 11:26:21]

Done.

+                              "memory reducer background GC");
   }
 }