DevTools: sync timeline and tracing grid times in timeline panel.

TBR=yurys
NOTRY=true

Review URL: https://codereview.chromium.org/277153003

git-svn-id: svn://svn.chromium.org/blink/trunk@173830 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: improve touch UX when navigating flame chart.

TBR=yurys
NOTRY=true

Review URL: https://codereview.chromium.org/279063003

git-svn-id: svn://svn.chromium.org/blink/trunk@173831 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: follow up to r173831: do not schedule update on updating scrollbar.

TBR=yurys

Review URL: https://codereview.chromium.org/277193002

git-svn-id: svn://svn.chromium.org/blink/trunk@173832 bbb929c8-8fbe-4397-9dbb-9b2b20218538