DevTools: Remove unneeded willReceiveResourceData instrumentation and reuse didReceiveData instead of didReceiveResourceData.

R=eustas@chromium.org, pfeldman@chromium.org, caseq, pfeldman

Review URL: https://codereview.chromium.org/108103002

git-svn-id: svn://svn.chromium.org/blink/trunk@169647 bbb929c8-8fbe-4397-9dbb-9b2b20218538