Include gif image decoding in images/ on linux.

Include gif image decoding in images/ on linux.

Build SkImageDecoder_libgif in images project and link against
libgif on linux.

Ensure that the GIF decoder is used in skimage.

Requires a new dependency on libgif-dev when building on linux.

Committed: https://code.google.com/p/skia/source/detail?r=8627

[scroggo, 2013-04-11 16:50:56]

https://codereview.chromium.org/14029011/diff/1/gyp/images.gyp
File gyp/images.gyp (right):

https://codereview.chromium.org/14029011/diff/1/gyp/images.gyp#newcode105
gyp/images.gyp:105: '../src/images/SkImageDecoder_libpng.cpp',
senorblanco@, it looks like you added this line. Do I need a similar line for
SkImageDecoder_libgif? It seems to work without it.

[Stephen White, 2013-04-11 17:22:03]

On 2013/04/11 16:50:56, scroggo wrote:
> https://codereview.chromium.org/14029011/diff/1/gyp/images.gyp
> File gyp/images.gyp (right):
> 
> https://codereview.chromium.org/14029011/diff/1/gyp/images.gyp#newcode105
> gyp/images.gyp:105: '../src/images/SkImageDecoder_libpng.cpp',
> senorblanco@, it looks like you added this line. Do I need a similar line for
> SkImageDecoder_libgif? It seems to work without it.

Honestly, I have no idea.  Apparently I tried to remove it in r1654, and the gm
build broke (probably on Mac or Win).  So I put that change back in in r1655.

If it builds on all platforms without this line, feel free to skip it.

[djsollen, 2013-04-11 18:25:33]

lgtm with one nit

https://codereview.chromium.org/14029011/diff/1/gyp/images.gyp
File gyp/images.gyp (right):

https://codereview.chromium.org/14029011/diff/1/gyp/images.gyp#newcode100
gyp/images.gyp:100: # Any targets that depend on this target should link in
libpng and libgif and
libpng, libgif, and...

[scroggo, 2013-04-11 18:31:47]

https://codereview.chromium.org/14029011/diff/1/gyp/images.gyp
File gyp/images.gyp (right):

https://codereview.chromium.org/14029011/diff/1/gyp/images.gyp#newcode100
gyp/images.gyp:100: # Any targets that depend on this target should link in
libpng and libgif and
On 2013/04/11 18:25:33, djsollen wrote:
> libpng, libgif, and...

Done.

[scroggo, 2013-04-11 18:32:08]

Committed patchset #2 manually as r8627 (presubmit successful).