Change filter quality when scaling-down in drawImage

When calling drawImage with imageSmoothingEnabled = false, we use nearest
neighbor as the filter. In the spec, it doesn't specify that we need to
use nearest neighbor when scaling down, so this CL changes to use
kLow_FitlerQuality when scaling down.

BUG=269089

Review-Url: https://codereview.chromium.org/2157953002
Cr-Commit-Position: refs/heads/master@{#406824}
6 files changed