[heap] Remove VerifyAllObjectsBlack from VisitLiveObjects

Markbits should be verified in VerifyMarking and friends. The function
may also be used then e.g. iterating just black objects while
incremental marking is active for the fast promotion mode.

BUG=chromium:694255

Change-Id: Ia719a983fec27b2bae03f8c6c3332003a10e8823
Reviewed-on: https://chromium-review.googlesource.com/451363Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43669}

src/heap/mark-compact.cc

@@ -3453,17 +3453,6 @@ bool MarkCompactCollector::WillBeDeoptimized(Code* code) {
   return code->is_optimized_code() && code->marked_for_deoptimization();
 }
 
-
-#ifdef VERIFY_HEAP
-static void VerifyAllBlackObjects(MemoryChunk* page) {
-  LiveObjectIterator<kAllLiveObjects> it(page);
-  HeapObject* object = NULL;
-  while ((object = it.Next()) != NULL) {
-    CHECK(ObjectMarking::IsBlack(object));
-  }
-}
-#endif  // VERIFY_HEAP
-
 void MarkCompactCollector::RecordLiveSlotsOnPage(Page* page) {
   EvacuateRecordOnlyVisitor visitor(heap());
   VisitLiveObjects(page, &visitor, kKeepMarking);
@@ -3472,10 +3461,6 @@ void MarkCompactCollector::RecordLiveSlotsOnPage(Page* page) {
 template <class Visitor>
 bool MarkCompactCollector::VisitLiveObjects(MemoryChunk* page, Visitor* visitor,
                                             IterationMode mode) {
-#ifdef VERIFY_HEAP
-  VerifyAllBlackObjects(page);
-#endif  // VERIFY_HEAP
-
   LiveObjectIterator<kBlackObjects> it(page);
   HeapObject* object = nullptr;
   while ((object = it.Next()) != nullptr) {