XFA: Support PNG format in pdfium_test and add image diffing

samples/samples.gyp

Index: samples/samples.gyp
diff --git a/samples/samples.gyp b/samples/samples.gyp
index 0c8ee9366112ad181813aeb7bbd042f0e58f3081..9d316ec005861c3ef57188335d6123c2d1f5f294 100644
--- a/samples/samples.gyp
+++ b/samples/samples.gyp
@@ -15,6 +15,24 @@
       'target_name': 'pdfium_test',
       'sources': [
         'pdfium_test.cc',
+        'image_diff_png.cc',
+      ],
+    },
+    {
+      'target_name': 'pdfium_diff',

[Lei Zhang, 2015/02/05 22:11:08]

Not building this for GN?

[Tom Sepez, 2015/02/05 22:58:21]

Good catch.

+      'type': 'executable',
+      'variables': { 'enable_wexit_time_destructors': 1, },
+      'dependencies': [
+        '../pdfium.gyp:fxcodec',
+        '../third_party/third_party.gyp:safemath',
+      ],
+      'include_dirs': [
+        '../../',
+      ],
+      'sources': [
+        'image_diff.cc',
+        'image_diff_png.h',
+        'image_diff_png.cc',
       ],
     },
   ],