Update navigator-detached-no-crash.html test to use testharness.js.

That way, we no longer need to depend on an expected file that will be
outdated everytime we add something to Navigator.

BUG=None

Review URL: https://codereview.chromium.org/301193006

git-svn-id: svn://svn.chromium.org/blink/trunk@175342 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[CSS Grid Layout] Support span in auto-placement algorithm

Modify auto-placement algorithm in order to support span in both
definite and automatic positions.

This patch fixes examples like:
  grid-row: auto;
  grid-column: 2 / span 3;

And also:
  grid-row: auto;
  grid-column: span 3;

BUG=353789
TEST=fast/css-grid-layout/grid-item-auto-placement-definite-span.html
TEST=fast/css-grid-layout/grid-item-auto-placement-automatic-span.html

Review URL: https://codereview.chromium.org/196943026

git-svn-id: svn://svn.chromium.org/blink/trunk@175343 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Replace Context::Scope with ScriptState::Scope

It's easy to misuse context. We should pass ScriptState around instead of contexts.

BUG=357144

Review URL: https://codereview.chromium.org/306853002

git-svn-id: svn://svn.chromium.org/blink/trunk@175344 bbb929c8-8fbe-4397-9dbb-9b2b20218538