Initialize V8 outside of PDFium.

samples/samples.gyp

 # Copyright 2014 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.
 
 {
   'target_defaults': {
     'type': 'executable',
     'dependencies': [
       '../pdfium.gyp:pdfium',
+      '<(DEPTH)/v8/tools/gyp/v8.gyp:v8_libplatform',
     ],
-    'include_dirs': ['<(DEPTH)'],
+    'include_dirs': [
+      '<(DEPTH)',
+      '<(DEPTH)/v8',
+      '<(DEPTH)/v8/include',
+    ],
   },
   'targets': [
     {
       'target_name': 'pdfium_test',
       'sources': [
         'pdfium_test.cc',
       ],
     },
   ],
 }