Changes look for scrollbars on windows (2)

Additionally respects the size from the OS.

BUG=333499 332937
TEST=none
R=jam@chromium.org, sadrul@chromium.org
TBR=sadrul@chromium.org

Review URL: https://codereview.chromium.org/143953007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246401 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246401