Allow building non-XFA (master) on the XFA branch.

samples/samples.gyp

Index: samples/samples.gyp
diff --git a/samples/samples.gyp b/samples/samples.gyp
index ff7b05823c88cd505f1a62ecc94981561d96f4f8..31fcbf7c72ffa457df2cc94f488fea5204922693 100644
--- a/samples/samples.gyp
+++ b/samples/samples.gyp
@@ -5,6 +5,7 @@
 {
   'variables': {
     'pdf_enable_v8%': 1,
+    'pdf_enable_xfa%': 1,
   },
   'target_defaults': {
     'defines' : [
@@ -27,6 +28,11 @@
           '<(DEPTH)/v8/include',
         ],
       }],
+      ['pdf_enable_xfa==1', {
+        'defines': [
+          'PDF_ENABLE_XFA',
+        ],
+      }],
     ],
   },
   'targets': [
@@ -51,6 +57,11 @@
         ],
       },
       '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',
@@ -71,6 +82,13 @@
         'image_diff_png.h',
         'image_diff_png.cc',
       ],
+      'conditions': [
+        ['pdf_enable_xfa==0', {
+          'dependencies': [
+            '../third_party/third_party.gyp:fx_lpng',
+          ],
+        }],
+      ],
     },
   ],
 }