Use enclosingIntRect for the cull rect of DrawingDisplayItems.

Pixel-snapping may change the bounds of the painted object, which affects the
"tightest" cull rect possible. Expanding to the enclosing int rect is safe and
still performant.

BUG=529938
TEST=fast/sub-pixel/sub-pixel-accumulates-to-layers.html

Review-Url: https://codereview.chromium.org/2128903002
Cr-Commit-Position: refs/heads/master@{#404224}
2 files changed