Switch from nonstd::unique_ptr to std::unique_ptr.

pdfium.gyp

 # Copyright 2015 PDFium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     # TODO(thakis): Enable this, pdfium:29
     #'chromium_code': 1,
     'pdf_use_skia%': 0,
     'pdf_enable_v8%': 1,
@@ skipping 714 matching lines @@
         'core/src/fpdftext/fpdf_text_int_unittest.cpp',
         'core/src/fxcodec/codec/fx_codec_jpx_unittest.cpp',
         'core/src/fxcrt/fx_basic_bstring_unittest.cpp',
         'core/src/fxcrt/fx_basic_memmgr_unittest.cpp',
         'core/src/fxcrt/fx_basic_wstring_unittest.cpp',
         'core/src/fxcrt/fx_bidi_unittest.cpp',
         'core/src/fxcrt/fx_extension_unittest.cpp',
         'core/src/fxcrt/fx_system_unittest.cpp',
         'testing/fx_string_testhelpers.h',
         'testing/fx_string_testhelpers.cpp',
-        'third_party/base/nonstd_unique_ptr_unittest.cpp',
       ],
     },
     {
       'target_name': 'pdfium_embeddertests',
       'type': 'executable',
       'dependencies': [
         '<(DEPTH)/testing/gmock.gyp:gmock',
         '<(DEPTH)/testing/gtest.gyp:gtest',
         'pdfium',
         'test_support',
@@ skipping 57 matching lines @@
           ],
           'dependencies': [
             '<(DEPTH)/v8/tools/gyp/v8.gyp:v8',
             '<(DEPTH)/v8/tools/gyp/v8.gyp:v8_libplatform',
           ],
         }],
       ],
     },
   ],
 }