Fix crash when dragging and dropping text in chrome://settings/startup

Fix crash when dragging and dropping text in chrome://settings/startup

BUG=132974
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=163141

[dcheng, 2012-10-18 00:20:57]

Note that I don't generally touch WebUI code, so if you feel the fix should be
at a different layer (e.g. we shouldn't be sending the dragDropStartupPage
message from the HTML), please push back =)

[Dan Beam, 2012-10-18 03:36:25]

I don't really know how the WebUI code would be expected to know if the model's
empty, but I'm fine with this change.  lgtm

[dcheng, 2012-10-18 17:42:52]

On 2012/10/18 03:36:25, Dan Beam wrote:
> I don't really know how the WebUI code would be expected to know if the
model's
> empty, but I'm fine with this change.  lgtm

I believe that due to http://crbug.com/122102, we are incorrectly dispatching a
drop event (note that in this case, dragover was not cancelled
(browser_options_startup_page_list.js:213) so the default behavior *should* be
to cancel potential drops).

[dcheng, 2012-10-19 01:02:40]

I've confirmed that we don't call event.preventDefault() in dragover, yet we
still get a drop event, which violates the spec. I will make the appropriate fix
in WebKit; at that point, I suspect we will no longer need this patch. Until
then, I will hold off on landing this patch.

[Dan Beam, 2012-10-19 04:27:10]

I'd personally prefer to land this now with a TODO() to remove when that bug is
fixed.

[commit-bot: I haz the power, 2012-10-19 22:43:11]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/[email protected]/11198049/4001

[commit-bot: I haz the power, 2012-10-20 04:12:17]

Change committed as 163141