Check pixelRef before attempting to ktx encode.

Check pixelRef before attempting to ktx encode.

If there is no pixelRef, do not attempt to dereference it.

This was caught running on Android, where we don't have the resources
folder (tracked in b/14406768). We fail to decode anything, and then
attempt to encode an SkBitmap without a pixelRef.

Committed: https://skia.googlesource.com/skia/+/c2dcf4a4a56027fd9129c1f170b79fb1af63011f

[krajcevski, 2014-07-02 21:48:28]

On 2014/07/02 21:45:43, scroggo wrote:

lgtm

[scroggo, 2014-07-02 21:48:47]

The CQ bit was checked by scroggo@google.com

[commit-bot: I haz the power, 2014-07-02 21:49:16]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/scroggo@google.com/362413005/1

[commit-bot: I haz the power, 2014-07-02 22:00:10]

Change committed as c2dcf4a4a56027fd9129c1f170b79fb1af63011f