Fix scrollbar buttons in classic windows theme. When I refactored the code

Fix scrollbar buttons in classic windows theme.  When I refactored the code
a few weeks ago, it seems a code path that was not being used before is now
called.  Added support to draw the scroll buttons in the correct orientation.

BUG=92773
TEST=Run chrome in classic windows theme.  Open the NTP and resize it to make
it small enough so that scroll bars appeat both horizontally and vertically.
Make sure all four scrollbar buttons appear in the correct orientation.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=86817

[Ben Goodger (Google), 2011-05-25 20:11:57]

LGTM

[commit-bot: I haz the power, 2011-05-26 14:17:53]

Change committed as 86817