[heap] Add a flag to disable remembered set verification.

BUG=chromium:720606

Review-Url: https://codereview.chromium.org/2871173006
Cr-Commit-Position: refs/heads/master@{#45252}

src/flag-definitions.h

@@ -700,6 +700,8 @@ DEFINE_BOOL(trace_detached_contexts, false,
 DEFINE_IMPLICATION(trace_detached_contexts, track_detached_contexts)
 #ifdef VERIFY_HEAP
 DEFINE_BOOL(verify_heap, false, "verify heap pointers before and after GC")
+DEFINE_BOOL(verify_heap_skip_remembered_set, false,
+            "disable remembered set verification")
 #endif
 DEFINE_BOOL(move_object_start, true, "enable moving of object starts")
 DEFINE_BOOL(memory_reducer, true, "use memory reducer")

src/heap/spaces.cc

@@ -1569,7 +1569,9 @@ void PagedSpace::Verify(ObjectVisitor* visitor) {
       // The object itself should look OK.
       object->ObjectVerify();
 
+      if (!FLAG_verify_heap_skip_remembered_set) {
         heap()->VerifyRememberedSetFor(object);
+      }
 
       // All the interior pointers should be contained in the heap.
       int size = object->Size();
@@ -3323,7 +3325,9 @@ void LargeObjectSpace::Verify() {
     // The object itself should look OK.
     object->ObjectVerify();
 
+    if (!FLAG_verify_heap_skip_remembered_set) {
       heap()->VerifyRememberedSetFor(object);
+    }
 
     // Byte arrays and strings don't have interior pointers.
     if (object->IsAbstractCode()) {