Reduce the number of #includes of compiler.h.

src/hydrogen-gvn.h

 // Copyright 2013 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.
 
 #ifndef V8_HYDROGEN_GVN_H_
 #define V8_HYDROGEN_GVN_H_
 
 #include <iosfwd>
 
-#include "src/compiler.h"
 #include "src/hydrogen.h"
 #include "src/hydrogen-instructions.h"
 #include "src/zone.h"
 
 namespace v8 {
 namespace internal {
 
 // This class extends GVNFlagSet with additional "special" dynamic side effects,
 // which can be used to represent side effects that cannot be expressed using
 // the GVNFlags of an HInstruction. These special side effects are tracked by a
@@ skipping 124 matching lines @@
   // Used when collecting side effects on paths from dominator to
   // dominated.
   BitVector visited_on_paths_;
 
   DISALLOW_COPY_AND_ASSIGN(HGlobalValueNumberingPhase);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_GVN_H_