Make DevTools support for the embedded SharedWorker.

Original patch is https://codereview.chromium.org/196503005/.
But it was reverted because of memory leaks.
https://codereview.chromium.org/223583002/

This is the fixed version.

BUG=327256

Review URL: https://codereview.chromium.org/223123003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@261432 0039d316-1c4b-4281-b951-d872f2087c98
17 files changed