Consolidate test support code.

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,
   },
   'target_defaults': {
     'defines' : [
@@ skipping 24 matching lines @@
         'fx_lpng',
         '../pdfium.gyp:pdfium',
         # Regardless of whether the library ships against system freetype,
         # always link this binary against the bundled one for consistency
         # of results across platforms.
         '../third_party/third_party.gyp:fx_freetype',
       ],
       'sources': [
         'pdfium_test.cc',
         'image_diff_png.cc',
+        '../testing/test_support.cpp',
+        '../testing/test_support.h',
       ],
       'link_settings': {
         'libraries!': [
           '-lfreetype',
         ],
       },
       'conditions': [
         ['pdf_enable_v8==1', {
           'dependencies': [
             '<(DEPTH)/v8/tools/gyp/v8.gyp:v8_libplatform',
@@ skipping 42 matching lines @@
         'fx_lpng/src/fx_pngset.c',
         'fx_lpng/src/fx_pngtrans.c',
         'fx_lpng/src/fx_pngwio.c',
         'fx_lpng/src/fx_pngwrite.c',
         'fx_lpng/src/fx_pngwtran.c',
         'fx_lpng/src/fx_pngwutil.c',
       ],
     },
   ],
 }