Add first-class support for user scripts

chrome/renderer/user_script_slave.h

Index: chrome/renderer/user_script_slave.h
diff --git a/chrome/renderer/user_script_slave.h b/chrome/renderer/user_script_slave.h
index 8232ec4ea771d0c5884f90d7a621515ac6fd1f02..3d7c49d75fb613287276b9a5c11f88b41cf71379 100644
--- a/chrome/renderer/user_script_slave.h
+++ b/chrome/renderer/user_script_slave.h
@@ -50,11 +50,6 @@ class UserScriptSlave {
   // Greasemonkey API source that is injected with the scripts.
   base::StringPiece api_js_;
 
-  // The line number of the first line of the user script among all of the
-  // injected javascript.  This is used to make reported errors correspond with
-  // the proper line in the user script.
-  int user_script_start_line_;
-
   DISALLOW_COPY_AND_ASSIGN(UserScriptSlave);
 };