Limit rate of full garbage collections triggered by idle notification.

src/heap/mark-compact.cc

Index: src/heap/mark-compact.cc
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
index de381aab356657374f1e62f083173045d949ded0..3d63bd12d1fe1285248f995bba18f024acd73c50 100644
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -53,7 +53,8 @@ MarkCompactCollector::MarkCompactCollector(Heap* heap)
       marking_deque_memory_(NULL),
       marking_deque_memory_committed_(false),
       code_flusher_(NULL),
-      have_code_to_deoptimize_(false) {
+      have_code_to_deoptimize_(false),
+      last_mark_compact_time_(0.0) {
 }
 
 #ifdef VERIFY_HEAP
@@ -878,6 +879,8 @@ void MarkCompactCollector::Finish() {
   }
 
   heap_->incremental_marking()->ClearIdleMarkingDelayCounter();
+  last_mark_compact_time_ =
+      V8::GetCurrentPlatform()->MonotonicallyIncreasingTime();
 }