Roll v8 to 0ff89ea7 and update gyp references

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.
 
 {
   'variables': {
     'pdf_enable_v8%': 1,
     'pdf_enable_xfa%': 0,  # Set to 1 in standalone builds by standalone.gypi.
     'pdf_use_skia%': 0,
   },
@@ skipping 46 matching lines @@
         ],
       },
       'conditions': [
         ['pdf_enable_xfa==0', {
           'dependencies': [
             '../third_party/third_party.gyp:fx_lpng',
           ],
         }],
         ['pdf_enable_v8==1', {
           'dependencies': [
-            '<(DEPTH)/v8/tools/gyp/v8.gyp:v8_libplatform',
+            '<(DEPTH)/v8/src/v8.gyp:v8_libplatform',
           ],
         }],
         ['pdf_use_skia==1', {
           'defines': ['PDF_ENABLE_SKIA'],
           'dependencies': [
             '<(DEPTH)/skia/skia.gyp:skia',
           ],
         }],
       ],
     },
@@ skipping 13 matching lines @@
       'conditions': [
         ['pdf_enable_xfa==0', {
           'dependencies': [
             '../third_party/third_party.gyp:fx_lpng',
           ],
         }],
       ],
     },
   ],
 }