Don't use RenderStyle::clone unless there is actually a RenderObject to attach the cloned style to.

Non-renderer-based elements such as optGroup do not have renderers.
BUG=348330
R=esprehn@chromium.org

Review URL: https://codereview.chromium.org/185293011

git-svn-id: svn://svn.chromium.org/blink/trunk@168394 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Properly handle a NULL webwidget returned from WebViewClient::createPopupMenu

The code path resulting in a NULL here currently segfaults, but will return
NULL after the Chromium-side patch https://codereview.chromium.org/185653006/

BUG=347901

Review URL: https://codereview.chromium.org/183833014

git-svn-id: svn://svn.chromium.org/blink/trunk@168395 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: encapsulate presentation model in timeline view.

R=caseq@chromium.org

Review URL: https://codereview.chromium.org/180273023

git-svn-id: svn://svn.chromium.org/blink/trunk@168396 bbb929c8-8fbe-4397-9dbb-9b2b20218538