Use CDM_MODULE_VERSION from content_decryption_module.h.

TEST=Desktop builds are successful.

Review URL: https://codereview.chromium.org/56273004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233138 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 233138