There would be no functional changes or performance impacts from
this fix, but this can avoid potential misuses and UBsan's bad-casting reports.

BUG=280225
R=dmazzoni@chromium.org,inferno@chromium.org

Review URL: https://codereview.chromium.org/361563003

git-svn-id: svn://svn.chromium.org/blink/trunk@177407 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Consider subpixel accumulation when invalidating paint

Pass repaint rect as LayoutRect to
- RenderObject::invalidatePaintUsingContainer(),
- RenderLayerRepainter::setBackingNeedsRepaintInRect()
- CompositedLayerMapping::setContentsNeedDisplayInRect()
and add subpixel accumulation before passing to GraphicsLayer.

BUG=390605
TEST=fast/sub-pixel/repaint-subpixel-layer-in-subpixel-composited-layer.html
R=leviw@chromium.org

Review URL: https://codereview.chromium.org/353403006

git-svn-id: svn://svn.chromium.org/blink/trunk@177408 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Define WebScrollOffsetAnimationCurve

This defines WebScrollOffsetAnimationCurve, needed for implementing
the CSSOM Smooth Scroll API.

The Chromium side of this is http://crrev.com/112933005.

BUG=243871

Review URL: https://codereview.chromium.org/365903004

git-svn-id: svn://svn.chromium.org/blink/trunk@177409 bbb929c8-8fbe-4397-9dbb-9b2b20218538