Restore code removed temporarily for refactoring on WebApplicationCacheHost in Blink

To land Blink 183121 which changes the signature of
WebApplicationCacheHost::didReceiveDataForMainResource(), we had to
duplicate implementation in Chromium side. We chose to just remove the
implementation temporarily and restore after the Blink side change gets
rolled since the implementation was empty.

BUG=418885

Review URL: https://codereview.chromium.org/666563004

Cr-Commit-Position: refs/heads/master@{#300854}
3 files changed