[XHR] Clear m_receivedLength in clearResponse()

m_receivedLength was cleared in clearVariablesForLoading() since it was
never used after abort/finish of loading. But it is now used also for
generating ProgressEvent instances which are dispatched on error which
happens at the end of each algorithm.

For ProgressEvent generation, m_receivedLength is checked together with
m_response. It's more appropriate to clear it at the same time as
m_response.

BUG=none

Review URL: https://codereview.chromium.org/95003007

git-svn-id: svn://svn.chromium.org/blink/trunk@163225 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make FontCache forget about Font.

Font is a higher-level abstraction and FontCache shouldn't
know about it.

BUG=319475
R=eae,eseidel,ksakamoto@chromium.org

Review URL: https://codereview.chromium.org/99683004

git-svn-id: svn://svn.chromium.org/blink/trunk@163226 bbb929c8-8fbe-4397-9dbb-9b2b20218538