[ServiceWorker] pipe RequestContext and FrameType to ServiceWorker. [1/2 blink]

[1/2] blink: https://codereview.chromium.org/625513002/
[2/2] chromium: https://codereview.chromium.org/623663002/

BUG=411174,418469

Review URL: https://codereview.chromium.org/625513002

git-svn-id: svn://svn.chromium.org/blink/trunk@183130 bbb929c8-8fbe-4397-9dbb-9b2b20218538