Merged: [heap] Fix live object iterator bail out case.

Revision: f82a59a

BUG=chromium:714207
LOG=N
NOTRY=true
NOPRESUBMIT=true
NOTREECHECKS=true
R=mlippautz@chromium.org

Change-Id: Iae7b7032e1d72fe9574a61dc632d3411e1289109
Reviewed-on: https://chromium-review.googlesource.com/506072
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/branch-heads/5.9@{crosswalk-project#49}
Cr-Branched-From: fe9bb7e-refs/heads/5.9.211@{crosswalk-project#1}
Cr-Branched-From: 70ad237-refs/heads/master@{#44591}

src/heap/mark-compact-inl.h

@@ -152,16 +152,13 @@ HeapObject* LiveObjectIterator<T>::Next() {
         // However, if there is a black area at the end of the page, and the
         // last word is a one word filler, we are not allowed to advance. In
         // that case we can return immediately.
-        if (it_.Done()) {
+        if (!it_.Advance()) {
           DCHECK(HeapObject::FromAddress(addr)->map() ==
                  HeapObject::FromAddress(addr)
                      ->GetHeap()
                      ->one_pointer_filler_map());
           return nullptr;
         }
-        bool not_done = it_.Advance();
-        USE(not_done);
-        DCHECK(not_done);
         cell_base_ = it_.CurrentCellBase();
         current_cell_ = *it_.CurrentCell();
       }
@@ -223,7 +220,7 @@ HeapObject* LiveObjectIterator<T>::Next() {
     }
 
     if (current_cell_ == 0) {
-      if (!it_.Done() && it_.Advance()) {
+      if (it_.Advance()) {
         cell_base_ = it_.CurrentCellBase();
         current_cell_ = *it_.CurrentCell();
       }