Add gif sources to public.bzl.

This also removes SK_HAS_GIF_LIBRARY since it does not appear in the
code.

Change-Id: I6e4d6ed560eb2877e6db61edf15f6be832166b44
Reviewed-on: https://skia-review.googlesource.com/3752
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
diff --git a/public.bzl b/public.bzl
index b27336b..8636d29 100644
--- a/public.bzl
+++ b/public.bzl
@@ -84,6 +84,8 @@
         # Third Party
         "third_party/etc1/*.cpp",
         "third_party/etc1/*.h",
+        "third_party/gif/*.cpp",
+        "third_party/gif/*.h",
         "third_party/ktx/*.cpp",
         "third_party/ktx/*.h",
     ],
@@ -385,6 +387,7 @@
     "src/sksl",
     "src/utils",
     "third_party/etc1",
+    "third_party/gif",
     "third_party/ktx",
 ]
 
@@ -570,7 +573,6 @@
     "SK_SAMPLES_FOR_X",
     "SK_PDF_USE_SFNTLY",
     "SK_CODEC_DECODES_RAW",
-    "SK_HAS_GIF_LIBRARY",
     "SK_HAS_JPEG_LIBRARY",
     "SK_HAS_PNG_LIBRARY",
     "SK_HAS_WEBP_LIBRARY",
@@ -579,7 +581,6 @@
 DEFINES_ANDROID = [
     "SK_BUILD_FOR_ANDROID",
     "SK_CODEC_DECODES_RAW",
-    "SK_HAS_GIF_LIBRARY",
     "SK_HAS_JPEG_LIBRARY",
     "SK_HAS_PNG_LIBRARY",
     "SK_HAS_WEBP_LIBRARY",