File constructor understands lastModified.

BUG=164933

Review URL: https://codereview.chromium.org/74213009

git-svn-id: svn://svn.chromium.org/blink/trunk@162362 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert 162315 "Don't cancel form submissions for other frames if..."

The test added here is flakey on all the bots.
http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=http%2Ftests%2Fmisc%2Fform-target-iframe-inline-location-change.html

> Don't cancel form submissions for other frames if this frame changes location.
> 
> If a form which specifies a target is submitted via javascript, and a location
> change is scheduled before the form submission fires, the form submission will
> be cancelled, even though the location change is completely orthogonal. This
> patch ensures we cancel a form submission without a target specified, but not
> one targeted elsewhere.
> 
> BUG=319281
> TEST=http/tests/misc/form-target-iframe-inline-location-change.html
> 
> Review URL: https://codereview.chromium.org/67693003

TBR=japhet@chromium.org

Review URL: https://codereview.chromium.org/78443002

git-svn-id: svn://svn.chromium.org/blink/trunk@162363 bbb929c8-8fbe-4397-9dbb-9b2b20218538