DevTools: DataGrid: do not use ::after content for sort order icon.

Make sort order icon explicit. This will make styling more predictable.

BUG=

Review URL: https://codereview.chromium.org/732423006

git-svn-id: svn://svn.chromium.org/blink/trunk@185791 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: fix FlameChart scaling on zoom in/out

FlameChart._canvas.width doesn't depend on devicePixelRatio and doesn't change when zooming. This means that result of _timeToPosition were always limited by the canvas width.


BUG=429584

Review URL: https://codereview.chromium.org/751553002

git-svn-id: svn://svn.chromium.org/blink/trunk@185795 bbb929c8-8fbe-4397-9dbb-9b2b20218538