Fix the NaCl build.

gyp/images.gyp

Index: gyp/images.gyp
diff --git a/gyp/images.gyp b/gyp/images.gyp
index 93e95a42c1612d66b20bfdc1b68d569a2fc66fa0..6b14226d6db79940294bc56cdd670acb5c96b1be 100644
--- a/gyp/images.gyp
+++ b/gyp/images.gyp
@@ -96,7 +96,7 @@
             '../src/ports/SkImageDecoder_CG.cpp',
           ],
         }],
-        [ 'skia_os in ["linux", "freebsd", "openbsd", "solaris", "nacl"]', {
+        [ 'skia_os in ["linux", "freebsd", "openbsd", "solaris"]', {
           # Any targets that depend on this target should link in libpng, libgif, and
           # our code that calls it.
           # See http://code.google.com/p/gyp/wiki/InputFormatReference#Dependent_Settings
@@ -112,6 +112,21 @@
           },
           # end libpng/libgif stuff
         }],
+        [ 'skia_os == "nacl"', {
+          'sources!': [
+            '../src/images/SkImageDecoder_libgif.cpp',
+            '../src/images/SkMovie_gif.cpp',
+          ],
+          'link_settings': {
+            'sources': [
+              '../src/images/SkImageDecoder_libpng.cpp',
+            ],
+            'libraries': [
+              '-lpng',
+              '-lz',
+            ],
+          },
+        }],
         [ 'skia_os == "android"', {
           'include_dirs': [
              '../src/utils',