Add namespace and re-arrange PDFium's local copy of chromium /base.

third_party/base/template_util.h

 // Copyright (c) 2011 The Chromium 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 BASE_TEMPLATE_UTIL_H_
-#define BASE_TEMPLATE_UTIL_H_
+#ifndef PDFIUM_THIRD_PARTY_BASE_TEMPLATE_UTIL_H_
+#define PDFIUM_THIRD_PARTY_BASE_TEMPLATE_UTIL_H_
 
 #include <cstddef>  // For size_t.
 
+namespace pdfium {
 namespace base {
 
 template<class T, T v>
 struct integral_constant {
   static const T value = v;
   typedef T value_type;
   typedef integral_constant<T, v> type;
 };
 
 typedef integral_constant<bool, true> true_type;
 typedef integral_constant<bool, false> false_type;
 
 template <class T, class U> struct is_same : public false_type {};
 template <class T> struct is_same<T,T> : true_type {};
 
 template<bool B, class T = void>
 struct enable_if {};
 
 template<class T>
 struct enable_if<true, T> { typedef T type; };
 
 }  // namespace base
+}  // namespace pdfium
 
-#endif  // BASE_TEMPLATE_UTIL_H_
+#endif  // PDFIUM_THIRD_PARTY_BASE_TEMPLATE_UTIL_H_