Move useful printing backend code from chrome/service/cloud_print to printing/backend.

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/3945003

git-svn-id: http://src.chromium.org/svn/trunk/src/build@63772 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -392,6 +392,11 @@
           'NACL_WIN64',
         ],
       }],
+      ['OS=="linux" and chromeos==0 and target_arch!="arm"', {
+        'use_cups%': 1,
+      }, {
+        'use_cups%': 0,
+      }],
     ],
 
     # NOTE: When these end up in the Mac bundle, we need to replace '-' for '_'