Add linux printing module.

Review URL: http://codereview.chromium.org/27008

git-svn-id: http://src.chromium.org/svn/trunk/src/build@10136 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

SConscript.main

@@ -104,6 +104,7 @@ root_env = Environment(
     GOOGLEURL_DIR         = '$OBJ_ROOT/googleurl',
     MEDIA_DIR             = '$OBJ_ROOT/media',
     NET_DIR               = '$OBJ_ROOT/net',
+    PRINTING_DIR          = '$OBJ_ROOT/printing',
     RLZ_DIR               = '$OBJ_ROOT/rlz',
     SANDBOX_DIR           = '$OBJ_ROOT/sandbox',
     SDCH_DIR              = '$OBJ_ROOT/sdch',
@@ -196,6 +197,7 @@ sconscripts = root_env.ChromiumLoadComponentSConscripts(
     googleurl = '$GOOGLEURL_DIR/googleurl.scons',
     media = '$MEDIA_DIR/media.scons',
     net = '$NET_DIR/net.scons',
+    printing = '$PRINTING_DIR/printing.scons',
     rlz = '$RLZ_DIR/SConscript',
     sandbox = '$SANDBOX_DIR/sandbox.scons',
     sdch = '$SDCH_DIR/SConscript',