Make the selection loop with arrow keys in the autocomplete popup

Fixs 2 autocomplete popup related bugs:
- pressing enter when the autocomplete popup is showing but has no selection should not eat the enter key event.
- pressing the up/down arrow to move the selection when the first/last row is selected should clear the selection and then the selection should jump to the last/first row.

BUG=6694, 6692
TEST=Bring up the autocomplete popup (by typing some text in a form input). Use the up/down arrow to move the selection. When passing the last item, the selection should first be cleared and then should jump to the first item. Similar behavior expected in the other direction.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=8482

[Matt Perry, 2009-01-21 22:38:09]

lgtm

http://codereview.chromium.org/18466/diff/6/204
File third_party/WebKit/WebCore/platform/chromium/PopupMenuChromium.cpp (right):

http://codereview.chromium.org/18466/diff/6/204#newcode626
Line 626: // Don't eat the enter if nothing is selected.
Seems strange to me that the enter would propagate up if the popup menu is open,
but if that's the behavior of other browsers, that's fine.

[darin (slow to review), 2009-01-26 22:54:26]

I am in the process of upstreaming this change
here:https://bugs.webkit.org/show_bug.cgi?id=23553

Please note, I found several WebKit style violations in this change.  The WebKit
style guide is here:  http://webkit.org/coding/coding-style.html

(It may be wiser to make changes like this upstream first before committing them
locally.  Otherwise, it is easy for style violations and other nit-picky issues
to creep in that then cause merge conflicts later on.)

[darin (slow to review), 2009-01-26 23:07:50]

Upstreamed:
https://bugs.webkit.org/show_bug.cgi?id=23553