Add extern for AddonManager.getAddonByID, which was added by commit 4c3c150.

Signed-off-by: Seva Lotoshnikov <vlotoshnikov@gmail.com>

Author: juangj

javascript/firefox-driver/js/externs.js

@@ -50,6 +50,9 @@ nsIPrefBranch.prototype.getCharPref;
 nsIPrefBranch.prototype.getIntPref;
 
 
+var AddonManager;
+AddonManager.getAddonByID;
+
 
 // Constants on constants
 Components.resources.NS_ERROR_NO_INTERFACE;