Reviewed by Geoff Garen.

    Reviewed by Geoff Garen.

        <rdar://problem/4564131> WebPluginDatabase setAdditionalWebPlugInPaths needs to be per WebView

        Added some WebView SPI so that individual WebViews may have different plugin search paths.  There are some
        limitations with the approach taken here:

        - JavaScript may only access the global plugin DB.
        - When this SPI is in use, certain WebView methods may not give accurate results, such as +canShowMIMEType:.
        - This only works for plugins referenced using the <object> or <embed> tags; plugins that reside in non-standard
        file system locations may not be loaded directly into frames.

        None of these issues are important to the client that needs this SPI.  Rather than re-architect our entire
        plugin database, I think it is better to simply accept these limitations for now.

        * Plugins/WebPluginDatabase.h:
        Added "plugInPaths" ivar, so different plugin databases can have different search paths.
        * Plugins/WebPluginDatabase.m:
        (+[WebPluginDatabase installedPlugins]):
        Give the global plugin database the default plugin search paths.
        (+[WebPluginDatabase setAdditionalWebPlugInPaths:]):
        Removed static global; this method now sets the plugin paths on the global plugin database.
        (-[WebPluginDatabase setPlugInPaths:]):
        Setter method for plugin paths.
        (-[WebPluginDatabase close]):
        New method; called when the plugin database is no longer needed (when its WebView is being destroyed).
        (-[WebPluginDatabase init]):
        Don't refresh in -init, so that callers can set the DB's plugin path array before it refreshes.
        (-[WebPluginDatabase dealloc]):
        Moved here from near the bottom of the file.  Release new ivar.
        (-[WebPluginDatabase refresh]):
        Use the plugInPaths ivar instead of calling pluginLocations().
        Notify plugin packages when they are added to and removed from a plugin database.  A plugin package will
        unload itself when it is removed from all of its plugin databases.
        The only really tricky thing here is that the global MIME <-> view class registrations are only modified
        by the shared plugin DB.
        (+[WebPluginDatabase _defaultPlugInPaths]):
        Refactored from the old pluginLocations() function; returns the default set of plugin search paths.

        * Plugins/WebBasePluginPackage.h:
        * Plugins/WebBasePluginPackage.m:
        (-[WebBasePluginPackage dealloc]):
        Assert that this package has been removed from all of its containing plugin databases.
        (-[WebBasePluginPackage finalize]):
        ditto
        (-[WebBasePluginPackage wasAddedToPluginDatabase:]):
        Add plugin database to set.
        (-[WebBasePluginPackage wasRemovedFromPluginDatabase:]):
        Remove plugin database from set.  If it was the last DB, then unload the plugin package.

        * WebView/WebViewInternal.h:
        Added instance methods to find the view class or plugin package, given a MIME type or file extension.
        * WebView/WebViewPrivate.h:
        Added SPI to set plugin search paths per WebView.
        * WebView/WebView.m:
        (-[WebView _viewClass:andRepresentationClass:forMIMEType:]):
        New method; tries the global MIME <-> view map first; failing that, it checks the WebView's plugin DB.
        (-[WebView _close]):
        Close the plugin DB.
        (-[WebView _setAdditionalWebPlugInPaths:]):
        Create the plugin DB if necessary, and set its plugin paths.
        (-[WebView _pluginForMIMEType:]):
        Checks global plugin DB, falls back on WebView DB.
        (-[WebView _pluginForExtension:]):
        ditto
        (-[WebView _isMIMETypeRegisteredAsPlugin:]):
        ditto

        * WebCoreSupport/WebFrameBridge.m:
        (-[WebFrameBridge viewForPluginWithURL:attributeNames:attributeValues:MIMEType:DOMElement:loadManually:]):
        Use new WebView instance methods to look for plugins.
        (-[WebFrameBridge viewForJavaAppletWithFrame:attributeNames:attributeValues:baseURL:DOMElement:]):
        ditto
        (-[WebFrameBridge determineObjectFromMIMEType:URL:]):
        ditto

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@14947 268f45cc-cd09-0410-ab3c-d52691b4dbfc