Remove superfluous call to SetURL in DragDownloadItem.

Remove superfluous call to SetURL in DragDownloadItem.

The download item code tried to be helpful and make sure Blink could
navigate to download items dropped in a web contents by setting a file
URL in the drop data. Unfortunately, this doesn't work because
RenderViewHostImpl::DragTargetDragEnter filters out file URLs and
rewrites it to about:blank, and Blink happily navigates there instead of
the file.

As it turns out, this is unnecessary because Blink already converts the
filename to a URL when it attempts to turn drops into navigations so we
get this behavior for free by omitting the call to SetURL.

It also confuses some Linux file managers, causing them to link to the
file instead of making a copy when the item is dragged from the download
bar.

BUG=356794
TEST=drag download bar items to the desktop (should copy) and to another
     Chrome window (should navigate)

R=thakis@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=260334

[Nico, 2014-03-28 19:01:25]

Did you test windows and chromeos with this?

[dcheng, 2014-03-28 20:15:55]

On 2014/03/28 19:01:25, Nico wrote:
> Did you test windows and chromeos with this?

In fact, this actually fixes dragging download items to a web view to open it on
Windows / ChromeOS too (before they just got redirected to about:blank because
of the FilterURL call in RHVI::DragTargetDragEnter). I'll update the description
to reflect this.

[Nico, 2014-03-28 20:21:30]

lgtm stamp with a good TEST= line describing how to manually test this

[dcheng, 2014-03-28 20:24:17]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2014-03-28 20:25:40]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dcheng@chromium.org/217243003/1

[commit-bot: I haz the power, 2014-03-28 23:45:07]

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

[commit-bot: I haz the power, 2014-03-28 23:45:07]

Commit queue rejected this change because the description was changed
between the time the change entered the commit queue and the time it
was ready to commit. You can safely check the commit box again.

[dcheng, 2014-03-28 23:48:26]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2014-03-28 23:49:36]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dcheng@chromium.org/217243003/1

[commit-bot: I haz the power, 2014-03-29 01:24:45]

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

[commit-bot: I haz the power, 2014-03-29 01:24:46]

Try jobs failed on following builders:
  tryserver.chromium on linux_chromium_chromeos_rel

[dcheng, 2014-03-29 01:32:48]

Committed patchset #1 manually as r260334 (presubmit successful).