[breakpad] remove dependency on content_switches.cc

R=joi@chromium.org, scottmg@chromium.org
BUG=none

Review URL: https://codereview.chromium.org/104593008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239179 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239179