Simplify visitor marking mode tracking.

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

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 461 matching lines @@
   // Disallow allocation during weak processing.
   // It would be technically safe to allow allocations, but it is unsafe
   // to mutate an object graph in a way in which a dead object gets
   // resurrected or mutate a HashTable (because HashTable's weak processing
   // assumes that the HashTable hasn't been mutated since the latest marking).
   // Due to the complexity, we just forbid allocations.
   NoAllocationScope noAllocationScope(this);
 
   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())) {
   }
 
   m_threadLocalWeakCallbackStack->decommit();
 
   if (isMainThread()) {
     double timeForThreadLocalWeakProcessing = WTF::currentTimeMS() - startTime;
     DEFINE_STATIC_LOCAL(
@@ skipping 1197 matching lines @@
 
   // Resume all parked threads upon leaving this scope.
   ParkThreadsScope parkThreadsScope(this);
 
   // Try to park the other threads. If we're unable to, bail out of the GC.
   if (!parkThreadsScope.parkThreads())
     return;
 
   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);
     }
   }
 
   ScriptForbiddenIfMainThreadScope scriptForbidden;
 
   TRACE_EVENT2("blink_gc,devtools.timeline", "BlinkGCMarking", "lazySweeping",
                gcType == BlinkGC::GCWithoutSweep, "gcReason",
                gcReasonString(reason));
   double startTime = WTF::currentTimeMS();
 
@@ skipping 85 matching lines @@
 }
 
 void ThreadState::collectGarbageForTerminatingThread() {
   {
     // A thread-specific termination GC must not allow other global GCs to go
     // ahead while it is running, hence the termination GC does not enter a
     // safepoint. VisitorScope will not enter also a safepoint scope for
     // ThreadTerminationGC.
     GCForbiddenScope gcForbiddenScope(this);
     std::unique_ptr<Visitor> visitor =
-        Visitor::create(this, Visitor::ThreadLocalMarking);
+        Visitor::create(this, VisitorMarkingMode::ThreadLocalMarking);
 
     NoAllocationScope noAllocationScope(this);
 
     heap().commitCallbackStacks();
     preGC();
 
     // 1. Trace the thread local persistent roots. For thread local GCs we
     // don't trace the stack (ie. no conservative scanning) since this is
     // only called during thread shutdown where there should be no objects
     // on the stack.
@@ skipping 25 matching lines @@
     collectGarbage(BlinkGC::NoHeapPointersOnStack, BlinkGC::GCWithSweep,
                    BlinkGC::ForcedGC);
     size_t liveObjects = heap().heapStats().markedObjectSize();
     if (liveObjects == previousLiveObjects)
       break;
     previousLiveObjects = liveObjects;
   }
 }
 
 }  // namespace blink