Keep scaledHeight calculation across oID calls

Prior to this commit, scaledHeight was only computed for the first
onIncrementalDecode call, and if y-sampling was requested, forgotten for
subsequent calls.

Bug: skia:8235
Change-Id: I87e8c2ba1b6a07b589841b0d7fbe9325f6bad76f
Reviewed-on: https://skia-review.googlesource.com/c/191880
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
1 file changed