Get 6 more layout tests passing.

Get 6 more layout tests passing.

It seems at some point we disabled the platform
test folder entirely in order to disable some Mac
specific tests and in the process disabled some
Windows tests because they appear in a sub-folder
of the platform folder.

This change makes us pass 6 more tests from platform/win/fast/events/,
tests which needed the function dispatchMessage
(and a few properties) added to TestShell.

I also implemented the IS_NUMPAD modifier on
the Keyboard event.

A good test that relies on dispatchMessage, the
properties and the NumPad detection is:

LayoutTests\platform\win\fast\events\keyLocation-numpad.html.

Note: This folder also contains...
LayoutTests/platform/win/editing/shift-page-up-down.html
... which was added to the defer list for now.

Review URL: http://codereview.chromium.org/21113

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@9316 0039d316-1c4b-4281-b951-d872f2087c98