Mark http/tests/images/webp-partial-load.html as flaky.

TBR=yurys@chromium.org
BUG=313846

Review URL: https://codereview.chromium.org/54103006

git-svn-id: svn://svn.chromium.org/blink/trunk@161093 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Be sure to repaint if we're scrolling a marquee.

I missed a case in https://chromiumcodereview.appspot.com/10989063 where repainting
was required: marquees. This patch adds a check for that case and updates the
layout test.

R=jchaffraix@chromium.org
BUG=313595

Review URL: https://codereview.chromium.org/50493016

git-svn-id: svn://svn.chromium.org/blink/trunk@161094 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Have SelectorQuery API take rootNode by reference

Have SelectorQuery API take rootNode by reference instead of taking a pointer
as it is expected to be non-null. This also gets rid of several unnecessary
null checks.

R=adamk

Review URL: https://codereview.chromium.org/53683007

git-svn-id: svn://svn.chromium.org/blink/trunk@161095 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Have Node::lastDescendant() return a reference

Have Node::lastDescendant() return a reference instead of a pointer
as it can never return null. It makes the calling code look safer
and gets rid of several unnecessary null checks.

Also get rid of Node::firstDescendant() which is unused.

R=adamk

Review URL: https://codereview.chromium.org/54803003

git-svn-id: svn://svn.chromium.org/blink/trunk@161096 bbb929c8-8fbe-4397-9dbb-9b2b20218538