We should be testing injecting user scripts on MediaDocument, PluginDocument, and ImageDocument. These follow a different code path to have scripts injected (their documents are custom-built), and this should be tested. We had a bug where start scripts weren't injected for these documents, and this was fixed in http://trac.webkit.org/changeset/66129 and http://trac.webkit.org/changeset/61271, but wasn't tested.
Created attachment 65632 [details] [PATCH] Tests
Comment on attachment 65632 [details] [PATCH] Tests r=me
Landed in r66144.
Tests added in http://trac.webkit.org/changeset/66144 seem to be failing on Snow Leopard (WebKit2): @@ -1,5 +1,2 @@ -CONSOLE MESSAGE: line 1: Start Script -CONSOLE MESSAGE: line 1: End Script -CONSOLE MESSAGE: line 1: Start Script -CONSOLE MESSAGE: line 1: End Script +CONSOLE MESSAGE: line 6: TypeError: Result of expression 'window.layoutTestController.addUserScript' [undefined] is not a function.