Make the embedder responsible for creating the WebFrame

Source/web/WebHelperPluginImpl.h

Index: Source/web/WebHelperPluginImpl.h
diff --git a/Source/web/WebHelperPluginImpl.h b/Source/web/WebHelperPluginImpl.h
index 0b06b32aa19a3ab5c9d210661cf2b09385cb08f5..d7ed9d3ebabd36b7437235991530e3ad8c70ed5a 100644
--- a/Source/web/WebHelperPluginImpl.h
+++ b/Source/web/WebHelperPluginImpl.h
@@ -43,7 +43,7 @@ namespace WebKit {
 
 class HelperPluginChromeClient;
 class WebDocument;
-class WebFrame;
+class WebFrameImpl;
 class WebViewImpl;
 class WebWidgetClient;
 
@@ -75,6 +75,7 @@ private:
 
     WebWidgetClient* m_widgetClient;
     WebViewImpl* m_webView;
+    WebFrameImpl* m_mainFrame;
     OwnPtr<WebCore::Page> m_page;
     OwnPtr<HelperPluginChromeClient> m_chromeClient;