[heap] Move IdentityMap data structure out of heap.

src/identity-map.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "src/heap/identity-map.h"
+#include "src/identity-map.h"
 
 #include "src/heap/heap.h"
 #include "src/zone-containers.h"
 
 namespace v8 {
 namespace internal {
 
 static const int kInitialIdentityMapSize = 4;
 static const int kResizeFactor = 4;
 
@@ skipping 166 matching lines @@
     DCHECK_GE(index, 0);
     values_[index] = old_values[i];
   }
 
   // Unregister old keys and register new keys.
   heap_->UnregisterStrongRoots(old_keys);
   heap_->RegisterStrongRoots(keys_, keys_ + size_);
 }
 }  // namespace internal
 }  // namespace v8