Fix the form autofill showing when pressing the up arrow key

When in a form text field, pressing the up/down arrow keys should bring up the autofill popup.
Pressing up would not trigger that behavior.
This happened because the default processing of the up arrow key is to move the caret to the beginning of the text input.
Showing the autofill is done as a posted task.
Because the caret was not at the end of the text-field by the time that task got executed, the popup would not show.
The fix is to not default process the up/down arrow key messages when an autofill popup will be shown.

Also fixed the WebViewImpl::HideAutoCompletePopup (harmless bug, calling it twice would cause it to hide the already hidden popup).

BUG=6437
TEST=Make sure up/down arrow keys trigger the autofill menu correctly (especially when there is already text in the text-field). Make sure autofill still works as expected.



Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=12428

[tim (not reviewing), 2009-03-25 00:02:17]

LGTM