Reviewed by Adam Barth.

        Add support for WebP image decoding in ImageDecoder
        using library libwebp-decode library available from
        http://www.webmproject.org/code/

        https://bugs.webkit.org/show_bug.cgi?id=47512

        Tests: fast/images/webp-image-decoding.html

        * CMakeLists.txt:
            add platform/image-decoders/webp files and directory
        * GNUmakefile.am:
            add platform/image-decoders/webp directory
        * WebCore.gyp/WebCore.gyp:
            add platform/image-decoders/webp directory
        * WebCore.gypi:
            add platform/image-decoders/webp directory
        * features.gypi:
            add WTF_USE_WEBP=1
        * platform/image-decoders/ImageDecoder.cpp:
        (WebCore::ImageDecoder::create):
            instantiate webp decoder for file starting with 'RIFF????WEBP'
        * platform/image-decoders/webp: Added.
        * platform/image-decoders/webp/WEBPImageDecoder.cpp: Added.
        (WebCore::WEBPImageDecoder::WEBPImageDecoder):
        (WebCore::WEBPImageDecoder::~WEBPImageDecoder):
        (WebCore::WEBPImageDecoder::isSizeAvailable):
        (WebCore::WEBPImageDecoder::frameBufferAtIndex):
        (WebCore::WEBPImageDecoder::decode):
            sub-class handling decoding of webp images
        * platform/image-decoders/webp/WEBPImageDecoder.h: Added.
        (WebCore::WEBPImageDecoder::filenameExtension):
        (WebCore::WEBPImageDecoder::supportsAlpha):
            header for webp-decoder sub-class
2010-10-17  Pascal Massimino  <pascal.massimino@gmail.com>
 
         Reviewed by Adam Barth.
 
         Add support for decoding WebP image
         https://bugs.webkit.org/show_bug.cgi?id=47512
 
         * DEPS:
           - Add dependency to libwebp.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@69942 268f45cc-cd09-0410-ab3c-d52691b4dbfc