Add enum that specifies the frame detachment reason.

public/web/WebFrame.h

Index: public/web/WebFrame.h
diff --git a/public/web/WebFrame.h b/public/web/WebFrame.h
index f43e83601d011dc08a36a9e62232b35d555a28a6..eb685d7dec586602861ca6419d6f43aea9d0d7b5 100644
--- a/public/web/WebFrame.h
+++ b/public/web/WebFrame.h
@@ -89,6 +89,9 @@ struct WebURLLoaderOptions;
 
 template <typename T> class WebVector;
 
+// Used in detach().
+enum class WebDetachReason { Remove, Swap };

[dcheng, 2015/05/29 22:01:21]

I would put this in WebFrameClient, since that's where we'll use it. I'd
probably define it inside WebFrameClient as well; that way, you can skip the
"Web" prefix.

+
 // Frames may be rendered in process ('local') or out of process ('remote').
 // A remote frame is always cross-site; a local frame may be either same-site or
 // cross-site.