Merge V8 5.3.332.45.  DO NOT MERGE

Test: Manual

FPIIM-449

Change-Id: Id3254828b068abdea3cb10442e0172a8c9a98e03
(cherry picked from commit 13e2dadd00298019ed862f2b2fc5068bba730bcf)
diff --git a/src/heap/gc-tracer.cc b/src/heap/gc-tracer.cc
index 4bae0a4..2b1f06a 100644
--- a/src/heap/gc-tracer.cc
+++ b/src/heap/gc-tracer.cc
@@ -135,6 +135,26 @@
   previous_ = previous_incremental_mark_compactor_event_ = current_;
 }
 
+void GCTracer::ResetForTesting() {
+  cumulative_incremental_marking_steps_ = 0.0;
+  cumulative_incremental_marking_bytes_ = 0.0;
+  cumulative_incremental_marking_duration_ = 0.0;
+  cumulative_pure_incremental_marking_duration_ = 0.0;
+  longest_incremental_marking_step_ = 0.0;
+  cumulative_incremental_marking_finalization_steps_ = 0.0;
+  cumulative_incremental_marking_finalization_duration_ = 0.0;
+  longest_incremental_marking_finalization_step_ = 0.0;
+  cumulative_marking_duration_ = 0.0;
+  cumulative_sweeping_duration_ = 0.0;
+  allocation_time_ms_ = 0.0;
+  new_space_allocation_counter_bytes_ = 0.0;
+  old_generation_allocation_counter_bytes_ = 0.0;
+  allocation_duration_since_gc_ = 0.0;
+  new_space_allocation_in_bytes_since_gc_ = 0.0;
+  old_generation_allocation_in_bytes_since_gc_ = 0.0;
+  combined_mark_compact_speed_cache_ = 0.0;
+  start_counter_ = 0;
+}
 
 void GCTracer::Start(GarbageCollector collector, const char* gc_reason,
                      const char* collector_reason) {