GC: IncrementalMarking: Add missing member initialization to constructor

src/heap/incremental-marking.cc

Index: src/heap/incremental-marking.cc
diff --git a/src/heap/incremental-marking.cc b/src/heap/incremental-marking.cc
index 343fd80ae44b8b5303f895bfa0462560a83b0a80..106b72e3c9729feeaa1069d0e8e2723edbfb0405 100644
--- a/src/heap/incremental-marking.cc
+++ b/src/heap/incremental-marking.cc
@@ -26,19 +26,24 @@ IncrementalMarking::StepActions IncrementalMarking::NoForcedStepActions() {
 IncrementalMarking::IncrementalMarking(Heap* heap)
     : heap_(heap),
       state_(STOPPED),
+      is_compacting_(false),
       steps_count_(0),
       old_generation_space_available_at_start_of_incremental_(0),
       old_generation_space_used_at_start_of_incremental_(0),
+      bytes_rescanned_(0),
       should_hurry_(false),
       marking_speed_(0),
+      bytes_scanned_(0),
       allocated_(0),
+      write_barriers_invoked_since_last_step_(0),
       idle_marking_delay_counter_(0),
       no_marking_scope_depth_(0),
       unscanned_bytes_of_large_object_(0),
       was_activated_(false),
       weak_closure_was_overapproximated_(false),
       weak_closure_approximation_rounds_(0),
-      request_type_(COMPLETE_MARKING) {}
+      request_type_(COMPLETE_MARKING),
+      gc_callback_flags_(kNoGCCallbackFlags) {}
 
 
 void IncrementalMarking::RecordWriteSlow(HeapObject* obj, Object** slot,