Avoid duplicate class for mark compact

Renamed BitmapSetSlowPathVisitor to MCBitmapSetSlowPathVisitor for
the mark compact case.

Bug: 29413717
Change-Id: Ibb85acc8e796c0b8208b13c468b5510b0cec47e1
diff --git a/runtime/gc/collector/mark_compact.cc b/runtime/gc/collector/mark_compact.cc
index 6beb606..61a9c9c 100644
--- a/runtime/gc/collector/mark_compact.cc
+++ b/runtime/gc/collector/mark_compact.cc
@@ -129,7 +129,7 @@
       false, GetTimings(), GetCurrentIteration()->GetClearSoftReferences(), this);
 }
 
-class BitmapSetSlowPathVisitor {
+class MCBitmapSetSlowPathVisitor {
  public:
   void operator()(const mirror::Object* obj) const SHARED_REQUIRES(Locks::mutator_lock_) {
     // Marking a large object, make sure its aligned as a sanity check.
@@ -155,7 +155,7 @@
       }
     } else {
       DCHECK(!space_->HasAddress(obj));
-      BitmapSetSlowPathVisitor visitor;
+      MCBitmapSetSlowPathVisitor visitor;
       if (!mark_bitmap_->Set(obj, visitor)) {
         // This object was not previously marked.
         MarkStackPush(obj);