Remove relocation lock.

src/heap.h

Index: src/heap.h
diff --git a/src/heap.h b/src/heap.h
index 9e758aaa06441317d2952d32feb9eddb2a34de6f..3a76ee07c3c74569408e63e2f57486568c1882c3 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -1826,38 +1826,6 @@ class Heap {
 
   void CheckpointObjectStats();
 
-  // We don't use a ScopedLock here since we want to lock the heap
-  // only when FLAG_parallel_recompilation is true.
-  class RelocationLock {
-   public:
-    explicit RelocationLock(Heap* heap) : heap_(heap) {
-      if (FLAG_parallel_recompilation) {
-        heap_->relocation_mutex_->Lock();
-#ifdef DEBUG
-        heap_->relocation_mutex_locked_ = true;
-#endif  // DEBUG
-      }
-    }
-
-    ~RelocationLock() {
-      if (FLAG_parallel_recompilation) {
-#ifdef DEBUG
-        heap_->relocation_mutex_locked_ = false;
-#endif  // DEBUG
-        heap_->relocation_mutex_->Unlock();
-      }
-    }
-
-#ifdef DEBUG
-    static bool IsLocked(Heap* heap) {
-      return heap->relocation_mutex_locked_;
-    }
-#endif  // DEBUG
-
-   private:
-    Heap* heap_;
-  };
-
  private:
   Heap();
 
@@ -2327,11 +2295,6 @@ class Heap {
 
   MemoryChunk* chunks_queued_for_free_;
 
-  Mutex* relocation_mutex_;
-#ifdef DEBUG
-  bool relocation_mutex_locked_;
-#endif  // DEBUG;
-
   friend class Factory;
   friend class GCTracer;
   friend class DisallowAllocationFailure;