Fix X64 compilation on Windows.

Review URL: http://codereview.chromium.org/6334086

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6613 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/cctest/test-bignum-dtoa.cc

-// Copyright 2010 the V8 project authors. All rights reserved.
+// Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
@@ -44,7 +44,7 @@ using namespace v8::internal;
 // Removes trailing '0' digits.
 // Can return the empty string if all digits are 0.
 static void TrimRepresentation(Vector<char> representation) {
-  int len = strlen(representation.start());
+  int len = StrLength(representation.start());
   int i;
   for (i = len - 1; i >= 0; --i) {
     if (representation[i] != '0') break;