UI nits for settings app - fix margins and avoid a workaround on touchscreens. 

BUG=161953,165707
TEST=Settings App margins should be balanced, at 20px. On Windows 8, with a
     touch screen, the margin should be the same (rather than margins for
     subheadings approaching 0).

Review URL: https://chromiumcodereview.appspot.com/11485021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@172826 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed