is specified.
https://bugs.webkit.org/show_bug.cgi?id=48046

Reviewed by Eric Carlson.

WebKit/mac: 

If a MIME type is specified in an object or embed element, and that MIME
type isn't supported by an installed plug-in, WebKit shouldn't attempt
to find a plug-in based on the file extension of the url attribute.
Doing so can lead to cases where a plug-in is loaded that can't handle
resources of the MIME type specified by the author.

* WebCoreSupport/WebFrameLoaderClient.mm:
(WebFrameLoaderClient::createPlugin): Only check for a pluginPackage by
extension if MIME type is the empty string.

LayoutTests: 

* plugins/invalid-mime-with-valid-extension-shows-missing-plugin-expected.txt: Added.
* plugins/invalid-mime-with-valid-extension-shows-missing-plugin.html: Added.
* plugins/resources/test.testnetscape: Added.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@70332 268f45cc-cd09-0410-ab3c-d52691b4dbfc