DOM UI options handler cleanup:

- improve StripColon
- remove superfluous parens (clang would catch these if they weren't inside ifdefs)
- move a couple more files to the abbreviated string definition style
- use SetBoolean rather than SetString("true")

BUG=none
TEST=trybots

Review URL: http://codereview.chromium.org/6490016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@74860 0039d316-1c4b-4281-b951-d872f2087c98