tree 16ecfdede3939dcd7f1b3db311371d974477e7c5
parent 79da63fa0bec40b560597c79c2e1231fa51aef36
author msarett <msarett@google.com> 1444414054 -0700
committer Commit bot <commit-bot@chromium.org> 1444414054 -0700

Fill incomplete images in SkCodec parent class

Rather than implementing some sort of "fill" in every
SkCodec subclass for incomplete images, let's make the
parent class handle this situation.

This includes an API change to SkCodec.h

SkCodec::getScanlines() now returns the number of lines it
read successfully, rather than an SkCodec::Result enum.
getScanlines() most often fails on an incomplete input, in
which case it is useful to know how many lines were
successfully decoded - this provides more information than
kIncomplete vs kSuccess.  We do lose information when the
API is used improperly, as we are no longer able to return
kInvalidParameter or kScanlineNotStarted.

Known Issues:
Does not work for incomplete fFrameIsSubset gifs.
Does not work for incomplete icos.

BUG=skia:

Review URL: https://codereview.chromium.org/1332053002