Reviewed by Dan Bernstein.
        
        Use the C++ stream object in WebBaseNetscapePluginView. Use a HashSet of RefPtrs to keep track of the streams.
        
        * Plugins/WebBaseNetscapePluginStream.mm:
        (WebNetscapePluginStream::~WebNetscapePluginStream):
        (WebNetscapePluginStream::setPlugin):
        (WebNetscapePluginStream::startStream):
        (WebNetscapePluginStream::destroyStream):
        (WebNetscapePluginStream::destroyStreamWithReason):
        (WebNetscapePluginStream::cancelLoadAndDestroyStreamWithError):
        (WebNetscapePluginStream::deliverData):
        * Plugins/WebBaseNetscapePluginView.h:
        * Plugins/WebBaseNetscapePluginView.mm:
        (-[WebBaseNetscapePluginView stop]):
        (-[WebBaseNetscapePluginView initWithFrame:pluginPackage:URL:baseURL:MIMEType:attributeKeys:attributeValues:loadManually:DOMElement:]):
        (-[WebBaseNetscapePluginView disconnectStream:]):
        (-[WebBaseNetscapePluginView dealloc]):
        (-[WebBaseNetscapePluginView pluginView:receivedResponse:]):
        (-[WebBaseNetscapePluginView pluginView:receivedData:]):
        (-[WebBaseNetscapePluginView pluginView:receivedError:]):
        (-[WebBaseNetscapePluginView pluginViewFinishedLoading:]):
        (-[WebBaseNetscapePluginView loadRequest:inTarget:withNotifyData:sendNotification:]):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@37915 268f45cc-cd09-0410-ab3c-d52691b4dbfc