ServiceWorker: Read the blob from SW's response to a fetch event
Also remove browser tests for the fetch event that will be replaced with layout
tests in the next Blink patch. Since layout tests can't test HTTP response
headers, one of the browser tests remains.
Multi-sided patch to implement blob-type fetch event
response bodies:
#1: blink-side: https://codereview.chromium.org/
307063002/
#2: chromium-side, THIS PATCH
#3: blink-side: https://codereview.chromium.org/
304233017
BUG=379074
Review URL: https://codereview.chromium.org/
304153015
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@274773 0039d316-1c4b-4281-b951-d872f2087c98