Remove grab-bag includes of v8.h from everywhere.

src/messages.h

 // Copyright 2006-2008 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.
 
 // The infrastructure used for (localized) message reporting in V8.
 //
 // Note: there's a big unresolved issue about ownership of the data
 // structures used by this framework.
 
 #ifndef V8_MESSAGES_H_
 #define V8_MESSAGES_H_
 
 #include "src/base/smart-pointers.h"
+#include "src/handles.h"
 #include "src/list.h"
 
 namespace v8 {
 namespace internal {
 
 // Forward declarations.
 class JSMessageObject;
 class LookupIterator;
 class SourceInfo;
 
@@ skipping 456 matching lines @@
 
   static MUST_USE_RESULT MaybeHandle<String> GetStringifiedProperty(
       Isolate* isolate, LookupIterator* property_lookup,
       Handle<String> default_value);
 
   List<Handle<JSObject> > visited_;
 };
 } }  // namespace v8::internal
 
 #endif  // V8_MESSAGES_H_