chrome.screenlockPrivate.showButton(), onButtonClicked()
BUG=320156

Review URL: https://codereview.chromium.org/107343002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241435 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241435
[Telemetry] Add thread duration for Async slices

An async event can theoritically start on a thread and end on another
but in practice that does not happen.

This CL calculates the thread_duration for async slices that started
and ended on the same thread.

BUG=329059

Review URL: https://codereview.chromium.org/112593004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241437 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241437