Layout test for <rdar://problem/4214080> document.embeds:
         embeds[0].Play() undefined at languageguide.org prevents audio playing
         on mouseover

         * fast/dom/object-embed-plugin-scripting-expected.txt: Added.
         * fast/dom/object-embed-plugin-scripting.html: Added.
         * fast/dom/resources/articles.m4a: Added.

WebCore:

         Reviewed by darin.

         - Fixed <rdar://problem/4214080> document.embeds: embeds[0].Play()
         undefined at languageguide.org prevents audio playing on mouseover

         - Layout test: fast/dom/object-embed-plugin-scripting.html

         A common idiom the kids like to use these days for plugins is to nest
         an <embed> inside an <object>, and assume that IE will honor the first,
         Mozilla the second. We happen to honor both, but the rules dictate that
         only the outer <object> gets a plugin/renderer. (A plugin is a
        renderer.) This is a problem because sites ID us as Mozilla and
        therefore attempt to script their plugins through the <embed>, which
        has no plugin/renderer. The fix here is to have an <embed> return its
        parent node's plugin/renderer when queried, if and only if it has no
        renderer of its own and its parent node is an <object>. We may decide
        to restrict this further in the future.

        One happy consequence of this patch is that all the apple.com Quicktime
        websites we had previously broken with TOT are now fixed.

        * khtml/html/html_objectimpl.cpp:
        (DOM::HTMLEmbedElementImpl::getEmbedInstance): The "if (!r)" clause
        implements the logic I just described. The code below it I changed
        just for style, to match the style in getObjectInstance().

        (DOM::HTMLEmbedElementImpl::rendererIsNeeded): Assert that an <object>
        parent has a renderer because we're going to use it later.

        (DOM::HTMLObjectElementImpl::rendererIsNeeded): Changed to match style
        of HTMLEmbedElementImpl counterpart.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@11873 268f45cc-cd09-0410-ab3c-d52691b4dbfc