[HTMLParser] Always start pumping new chunks after unpausing.

Pauses may happen while the parser has already yielded, and in
particular when a script-inserted style sheet appears that has
an external resource.

The failure mode before this patch was:
1. Yield & schedule unyield
2. Script task runs
3. Script task inserts stylesheet with external resource
4. Resource finished
5. ResumeParsingAfterPause called, but there is no last_chunk_before_pause_
because there was a yield, not a pause.

Bug:902237

Change-Id: Id65c721fc193ecec7190e6b466a6794b65ea6acc
Reviewed-on: https://chromium-review.googlesource.com/c/1389502
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622099}
1 file changed