plug-ins are disabled

Reviewed by Anders Carlsson.

Ensure that the shared WebPluginDatabase is not instantiated if no
WebViews are used that have plug-ins enabled.

* DefaultDelegates/WebDefaultPolicyDelegate.m:
(-[WebDefaultPolicyDelegate webView:decidePolicyForMIMEType:request:frame:decisionListener:]):
Call -[WebView _canShowMIMEType:] on the WebView instead of calling the
class method.

* WebCoreSupport/WebFrameLoaderClient.mm:
(WebFrameLoaderClient::canShowMIMEType): Ditto.
(WebFrameLoaderClient::transitionToCommittedForNewPage): Call
-[WebFrameView _viewClassForMIMEType:] on the WebView instead of calling
the class method.
(WebFrameLoaderClient::objectContentType): Ditto.

* WebView/WebDataSource.mm:
(+[WebDataSource _representationClassForMIMEType:allowingPlugins:]):
Added the allowPlugins parameter, which is passed through to
+[WebView _viewClass:andRepresentationClass:forMIMEType:allowingPlugins:].
(-[WebDataSource _makeRepresentation]): Pass an allowPlugins value
based on the WebView’s preferences.

* WebView/WebFrameView.mm:
(-[WebFrameView _makeDocumentViewForDataSource:]): Call
-[WebFrameView _viewClassForMIMEType:] instead of calling the class
method.
(+[WebFrameView _viewClassForMIMEType:allowingPlugins:]): Added the
allowPlugins parameter, which is passed through to
+[WebView _viewClass:andRepresentationClass:forMIMEType:allowingPlugins:].
(-[WebFrameView _viewClassForMIMEType:]): Added. Passes an allowPlugins
value based on the WebView’s preferences.

* WebView/WebFrameViewInternal.h:
* WebView/WebView.mm:
(+[WebView _viewClass:andRepresentationClass:forMIMEType:allowingPlugins:]):
Added the allowPlugins parameter. If false, skip the instantiation of
the shared WebPluginDatabase.
(-[WebView _viewClass:andRepresentationClass:forMIMEType:]): Pass an
allowPlugins value based on the WebView’s preferences.
(+[WebView _canShowMIMEType:allowingPlugins:]): Passes allowPlugins to
+_viewClass:andRepresentationClass:forMIMEType:allowingPlugins:.
(+[WebView canShowMIMEType:]): Changed to pass YES to
+_canShowMIMEType:allowingPlugins:.
(-[WebView _canShowMIMEType:]): Added. Passes an allowPlugins value
based on the WebView’s preferences.
(-[WebView _pluginForMIMEType:]): Return nil if plug-ins are disabled.
(-[WebView _pluginForExtension:]): Ditto.
(-[WebView _isMIMETypeRegisteredAsPlugin:]): Return NO if plug-ins are
disabled.
* WebView/WebViewInternal.h:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@51617 268f45cc-cd09-0410-ab3c-d52691b4dbfc