Add ServiceWorkerContextClient::getClients() interface

To implement ServiceWorkerGlobalScope.clients:
https://github.com/slightlyoff/ServiceWorker/blob/master/service_worker.ts#L205

BUG=363965

Review URL: https://codereview.chromium.org/240253002

git-svn-id: svn://svn.chromium.org/blink/trunk@172023 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Fix Ctrl+Shift shortcut handling

Drive-by: be more lenient when detecting printable key press combinations.

R=vsevik@chromium.org, vsevik
NOTRY=true

Review URL: https://codereview.chromium.org/244913002

git-svn-id: svn://svn.chromium.org/blink/trunk@172024 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Send UpdateCounters event after each GC

Otherwise counter graphs may not be updated for a long period after GC.

BUG=304689

Review URL: https://codereview.chromium.org/243303004

git-svn-id: svn://svn.chromium.org/blink/trunk@172025 bbb929c8-8fbe-4397-9dbb-9b2b20218538