Remove several grab-bag includes from the v8.h header.

src/globals.h

 // Copyright 2012 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_GLOBALS_H_
 #define V8_GLOBALS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 497 matching lines @@
 enum VisitMode {
   VISIT_ALL,
   VISIT_ALL_IN_SCAVENGE,
   VISIT_ALL_IN_SWEEP_NEWSPACE,
   VISIT_ONLY_STRONG
 };
 
 // Flag indicating whether code is built into the VM (one of the natives files).
 enum NativesFlag { NOT_NATIVES_CODE, NATIVES_CODE };
 
+// JavaScript defines two kinds of 'nil'.
+enum NilValue { kNullValue, kUndefinedValue };
 
 // ParseRestriction is used to restrict the set of valid statements in a
 // unit of compilation.  Restriction violations cause a syntax error.
 enum ParseRestriction {
   NO_PARSE_RESTRICTION,         // All expressions are allowed.
   ONLY_SINGLE_FUNCTION_LITERAL  // Only a single FunctionLiteral expression.
 };
 
 // A CodeDesc describes a buffer holding instructions and relocation
 // information. The instructions start at the beginning of the buffer
@@ skipping 479 matching lines @@
 inline FunctionKind WithObjectLiteralBit(FunctionKind kind) {
   kind = static_cast<FunctionKind>(kind | FunctionKind::kInObjectLiteral);
   DCHECK(IsValidFunctionKind(kind));
   return kind;
 }
 } }  // namespace v8::internal
 
 namespace i = v8::internal;
 
 #endif  // V8_GLOBALS_H_