Reduce the number of #includes of compiler.h.

src/x64/assembler-x64.h

 // Copyright (c) 1994-2006 Sun Microsystems 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.
 //
@@ skipping 21 matching lines @@
 // modified significantly by Google Inc.
 // Copyright 2012 the V8 project authors. All rights reserved.
 
 // A lightweight X64 Assembler.
 
 #ifndef V8_X64_ASSEMBLER_X64_H_
 #define V8_X64_ASSEMBLER_X64_H_
 
 #include <deque>
 
+#include "src/assembler.h"
 #include "src/serialize.h"
 
 namespace v8 {
 namespace internal {
 
 // Utility functions
 
 // CPU Registers.
 //
 // 1) We would prefer to use an enum, but enum values are assignment-
@@ skipping 1800 matching lines @@
  private:
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_ASSEMBLER_X64_H_