[Patch] GdkPixbuf's GIF loader should set invalid delay times to 100ms, not 20ms

["John Millikin" <jmillikin gmail com>]

(from http://bugzilla.gnome.org/show_bug.cgi?id=414143)

Currently, when the GIF loader detects an invalid or too fast GIF
delay time, the delay is set to 20ms. However, most other software
that deals with rendering potentially invalid GIFs (such as Epiphany
or Konqueror) set invalid delay times to 100ms. The result is that
applications that use the GdkPixbufAnimation class appear to render
GIFs "too fast", even though the GIF itself is at fault.

I actually think that the algorithm should set invalid times (0ms) to
100ms, and merely too short times (<20ms) to 20ms. A time of 0ms is
clearly erroneous, and should be corrected. However, a very short
non-zero time indicates the author of the animation intended it to be
fast.

I have created two patches, one for the existing behaviour of other
software, and another for the second correction system. Both are
attached to the bug report.