change pages while a plugin is tracking.

        * Plugins.subproj/WebPluginView.h: Add sendEvent and sendUpdateEvent.
	Remove the NPP_HandleEvent method.
        * Plugins.subproj/WebPluginView.m:
        (-[WebNetscapePluginView sendEvent:]): Sets up the "defersCallbacks"
	state, then sends the event.

        * Plugins.subproj/WebNetscapePluginViewPrivate.h: Added.
	This stuff was shared in a different way before, and it
	hadn't even been renamed.
        * WebKit.pbproj/project.pbxproj: Added file.
        * Plugins.subproj/npapi.m: Use the new private header.

        * Plugins.subproj/WebPluginNullEventSender.h: Hold a reference
	to the view.
        * Plugins.subproj/WebPluginNullEventSender.m:
        (-[WebNetscapePluginNullEventSender initWithPluginView:]):
	Retain the view.
        (-[WebNetscapePluginNullEventSender dealloc]): Release the view.
        (-[WebNetscapePluginNullEventSender sendNullEvents]): Use sendEvent:.
        (-[WebNetscapePluginNullEventSender stop]): No need for shouldStop.

        * WebView.subproj/WebDataSourcePrivate.m:
        (-[WebDataSourcePrivate init]): Don't set contentPolicy to an enum value,
	when it's an object reference.
        (-[WebDataSourcePrivate dealloc]): Release contentPolicy to fix a leak.

        * WebView.subproj/WebHTMLView.m:
        (-[WebHTMLView mouseDragged:]): Set draggedURL to nil in the else case,
	it was uninitialized before. Also center the icon better when dragging,
	but shouldn't we be dragging something more than the icon here?

        * Misc.subproj/WebIconDatabase.m: (-[WebIconDatabase defaultIconWithSize:]):
	Add a call to release. Doesn't really plug a leak, but cleaner this way.

        * Plugins.subproj/WebPlugin.m: Tweaks.
        * WebView.subproj/WebMainResourceClient.m: Tweaks only.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@1960 268f45cc-cd09-0410-ab3c-d52691b4dbfc