Linux: make current InitializeSandbox() private.

The current InitializeSandbox() is only usable from inside
of content/, make it part of the content-specific LinuxSandbox class.

BUG=229673
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/13814027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@194072 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed