[XHR] Reset m_downloadedBlobLength

[XHR] Reset m_downloadedBlobLength

When XMLHttpRequest.responseType is specified to "blob", we
download the resource into a file and on XMLHttpRequest.response
call, we create a Blob object from m_response.downloadedFilePath()
and m_downloadedBlobLength. m_downloadedBlobLength is accumulated on
WebCore::XMLHttpRequest::didDownloadData() handler call but not
reset on clearResponse() call. So, if you use the XHR instance again
after calling open(), uncleared invalid size will be used.

We should just reset it to 0 on clearResponse() call.

BUG=349321
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168531

[abarth-chromium, 2014-03-05 05:26:38]

Can you add more of a description?  Why do we need to reset
m_downloadedBlobLength?  What problem does that solve?  Why is this change the
best way of solving that problem?

[abarth-chromium, 2014-03-05 05:27:19]

That actual change LGTM, but please improve the description before landing.

[tyoshino (SeeGerritForStatus), 2014-03-05 05:28:43]

Updated, sorry

[abarth-chromium, 2014-03-05 05:30:09]

Perfect.  Thanks!!

[tyoshino (SeeGerritForStatus), 2014-03-05 05:31:07]

The CQ bit was checked by tyoshino@chromium.org

[tyoshino (SeeGerritForStatus), 2014-03-05 05:31:27]

The CQ bit was unchecked by tyoshino@chromium.org

[tyoshino (SeeGerritForStatus), 2014-03-05 05:31:42]

The CQ bit was checked by tyoshino@chromium.org

[commit-bot: I haz the power, 2014-03-05 05:32:50]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tyoshino@chromium.org/183333005/1

[commit-bot: I haz the power, 2014-03-05 05:55:39]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-05 05:55:39]

Retried try job too often on blink_presubmit for step(s) presubmit
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=blink_pres...

[tyoshino (SeeGerritForStatus), 2014-03-05 05:56:40]

The CQ bit was checked by tyoshino@chromium.org

[commit-bot: I haz the power, 2014-03-05 05:57:31]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tyoshino@chromium.org/183333005/1

[commit-bot: I haz the power, 2014-03-05 20:56:27]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tyoshino@chromium.org/183333005/1

[commit-bot: I haz the power, 2014-03-05 21:03:36]

Change committed as 168531