Cleanup various WebView/WebFrame APIs to properly handle remote frames.

Source/core/frame/Frame.cpp

Index: Source/core/frame/Frame.cpp
diff --git a/Source/core/frame/Frame.cpp b/Source/core/frame/Frame.cpp
index db3f719f5951b14d8bae71fdb31142411de8e2df..fb7136ddee8c414a225dbae26078b840ffedc64c 100644
--- a/Source/core/frame/Frame.cpp
+++ b/Source/core/frame/Frame.cpp
@@ -73,6 +73,8 @@ Frame::Frame(FrameClient* client, FrameHost* host, FrameOwner* owner)
         page()->incrementSubframeCount();
         if (m_owner->isLocal())
             toHTMLFrameOwnerElement(m_owner)->setContentFrame(*this);
+    } else {
+        page()->setMainFrame(this);
     }
 }