Simplify visitor marking mode tracking.

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

Index: third_party/WebKit/Source/platform/heap/ThreadState.cpp
diff --git a/third_party/WebKit/Source/platform/heap/ThreadState.cpp b/third_party/WebKit/Source/platform/heap/ThreadState.cpp
index e9bef27aff5f8c4fc9d2ebfa00cb9d6d571599b7..30ee76277ccb22279ee1f4bc62128aed1a830897 100644
--- a/third_party/WebKit/Source/platform/heap/ThreadState.cpp
+++ b/third_party/WebKit/Source/platform/heap/ThreadState.cpp
@@ -479,7 +479,7 @@ void ThreadState::threadLocalWeakProcessing() {
 
   GCForbiddenScope gcForbiddenScope(this);
   std::unique_ptr<Visitor> visitor =
-      Visitor::create(this, Visitor::WeakProcessing);
+      Visitor::create(this, VisitorMarkingMode::WeakProcessing);
 
   // Perform thread-specific weak processing.
   while (popAndInvokeThreadLocalWeakCallback(visitor.get())) {
@@ -1697,14 +1697,15 @@ void ThreadState::collectGarbage(BlinkGC::StackState stackState,
 
   std::unique_ptr<Visitor> visitor;
   if (gcType == BlinkGC::TakeSnapshot) {
-    visitor = Visitor::create(this, Visitor::SnapshotMarking);
+    visitor = Visitor::create(this, VisitorMarkingMode::SnapshotMarking);
   } else {
     DCHECK(gcType == BlinkGC::GCWithSweep || gcType == BlinkGC::GCWithoutSweep);
     if (heap().compaction()->shouldCompact(this, gcType, reason)) {
       heap().compaction()->initialize(this);
-      visitor = Visitor::create(this, Visitor::GlobalMarkingWithCompaction);
+      visitor = Visitor::create(
+          this, VisitorMarkingMode::GlobalMarkingWithCompaction);
     } else {
-      visitor = Visitor::create(this, Visitor::GlobalMarking);
+      visitor = Visitor::create(this, VisitorMarkingMode::GlobalMarking);
     }
   }
 
@@ -1810,7 +1811,7 @@ void ThreadState::collectGarbageForTerminatingThread() {
     // ThreadTerminationGC.
     GCForbiddenScope gcForbiddenScope(this);
     std::unique_ptr<Visitor> visitor =
-        Visitor::create(this, Visitor::ThreadLocalMarking);
+        Visitor::create(this, VisitorMarkingMode::ThreadLocalMarking);
 
     NoAllocationScope noAllocationScope(this);