[DevTools] Fix extensions in embedded remote frontend.

BUG=431697

Review URL: https://codereview.chromium.org/731253002

git-svn-id: svn://svn.chromium.org/blink/trunk@185525 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Make PieChart a web component

R=pfeldman

Review URL: https://codereview.chromium.org/727313002

git-svn-id: svn://svn.chromium.org/blink/trunk@185526 bbb929c8-8fbe-4397-9dbb-9b2b20218538