https://bugs.webkit.org/show_bug.cgi?id=33747

Reviewed by David Levin.

No tests since Safari doesn't use these decoders and there's already a
broken-image test in the tree.

* platform/graphics/ImageSource.cpp:
(WebCore::ImageSource::createFrameAtIndex): No need to check isSizeAvailable() since size() is now always safe.
* platform/image-decoders/ImageDecoder.h:
(WebCore::ImageDecoder::size): Don't assert that the bitmap is valid; we don't need a complete successful decode to be able to give info about the size.
* platform/image-decoders/qt/RGBA32BufferQt.cpp:
(WebCore::RGBA32Buffer::setSize): Don't set the frame to complete on failure, since it's not complete, but empty, and callers can better handle empty frames.
* platform/image-decoders/skia/ImageDecoderSkia.cpp:
(WebCore::RGBA32Buffer::setSize): Don't set the frame to complete on failure, since it's not complete, but empty, and callers can better handle empty frames.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@53884 268f45cc-cd09-0410-ab3c-d52691b4dbfc