Remove grab-bag includes of v8.h from several files.

src/cached-powers.cc

 // Copyright 2011 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/cached-powers.h"
+
 #include <limits.h>
 #include <stdarg.h>
 #include <stdint.h>
 #include <cmath>
 
 #include "src/base/logging.h"
-#include "src/cached-powers.h"
 #include "src/globals.h"
 
 namespace v8 {
 namespace internal {
 
 struct CachedPower {
   uint64_t significand;
   int16_t binary_exponent;
   int16_t decimal_exponent;
 };
@@ skipping 129 matching lines @@
       (requested_exponent + kCachedPowersOffset) / kDecimalExponentDistance;
   CachedPower cached_power = kCachedPowers[index];
   *power = DiyFp(cached_power.significand, cached_power.binary_exponent);
   *found_exponent = cached_power.decimal_exponent;
   DCHECK(*found_exponent <= requested_exponent);
   DCHECK(requested_exponent < *found_exponent + kDecimalExponentDistance);
 }
 
 }  // namespace internal
 }  // namespace v8