Avoid infinite background tile scale

The issue happened when an SVG background image was painted with a very
small background size rounded to zero, causing infinite tile scale and
DCHECK failure in ClipRectOp.

Bug: 1039762
Change-Id: Ia94ce2fd350b28696ef8068bd0e756bfc6d87a72
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2002839
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732572}
8 files changed