Track heap objects.

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index df420639a6a7f9cbc29219da24b6fee35f7c1cc9..da7c7a1896f6f127ff0e4ba3149a3a290b720a02 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -2333,7 +2333,9 @@ LInstruction* LChunkBuilder::DoStoreNamedField(HStoreNamedField* instr) {
   LOperand* temp = needs_write_barrier_for_map ? TempRegister() : NULL;
 
   LStoreNamedField* result = new(zone()) LStoreNamedField(obj, val, temp);
-  if (FLAG_track_fields && instr->field_representation().IsSmi()) {
+  if ((FLAG_track_fields && instr->field_representation().IsSmi()) ||
+      (FLAG_track_heap_object_fields &&
+       instr->field_representation().IsHeapObject())) {
     return AssignEnvironment(result);
   }
   return result;