Coding style: remove JS-like !! bool cast from browser_options_handler.cc

BUG=none

Review URL: https://codereview.chromium.org/197793002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257120 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 257120
[Mac] Don't crash when enumerating OS TTS voices if there is no default voice.

BUG=346156
R=dmazzoni@chromium.org

Review URL: https://codereview.chromium.org/196223012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257121 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 257121