Simplify visitor marking mode tracking.

third_party/WebKit/Source/platform/heap/Visitor.cpp

Index: third_party/WebKit/Source/platform/heap/Visitor.cpp
diff --git a/third_party/WebKit/Source/platform/heap/Visitor.cpp b/third_party/WebKit/Source/platform/heap/Visitor.cpp
index c5779694bebe4f1494017059b5701ffba3d77785..ed32a71ef22eb05e88e77013be2f458dc8192f76 100644
--- a/third_party/WebKit/Source/platform/heap/Visitor.cpp
+++ b/third_party/WebKit/Source/platform/heap/Visitor.cpp
@@ -12,12 +12,13 @@
 
 namespace blink {
 
-std::unique_ptr<Visitor> Visitor::create(ThreadState* state, MarkingMode mode) {
+std::unique_ptr<Visitor> Visitor::create(ThreadState* state,
+                                         VisitorMarkingMode mode) {
   return WTF::makeUnique<MarkingVisitor>(state, mode);
 }
 
-Visitor::Visitor(ThreadState* state, MarkingMode markingMode)
-    : VisitorHelper(state), m_markingMode(markingMode) {
+Visitor::Visitor(ThreadState* state, VisitorMarkingMode markingMode)
+    : VisitorHelper(state, markingMode) {
   // See ThreadState::runScheduledGC() why we need to already be in a
   // GCForbiddenScope before any safe point is entered.
   DCHECK(state->isGCForbidden());