Detach old frame on WebFrame::swap.

Source/core/frame/Frame.h

Index: Source/core/frame/Frame.h
diff --git a/Source/core/frame/Frame.h b/Source/core/frame/Frame.h
index bccaf64b1edd41d460a508173fbd9aa9b447ea3b..5137db7750e128ee4207c6b1b377b2c4caa7faa4 100644
--- a/Source/core/frame/Frame.h
+++ b/Source/core/frame/Frame.h
@@ -53,6 +53,8 @@ class Settings;
 class WindowProxy;
 class WindowProxyManager;
 
+enum class DetachType { Remove, Swap };

[dcheng, 2015/06/04 00:58:23]

Let's call this FrameDetachType if we're going to make it a top-level type.

[lfg, 2015/06/04 19:16:57]

Done.

+
 // Status of user gesture.
 enum class UserGestureStatus { Active, None };
 
@@ -71,7 +73,7 @@ public:
     virtual void navigate(Document& originDocument, const KURL&, bool lockBackForwardList, UserGestureStatus) = 0;
     virtual void reload(ReloadPolicy, ClientRedirectPolicy) = 0;
 
-    virtual void detach();
+    virtual void detach(DetachType);
     void detachChildren();
     virtual void disconnectOwnerElement();
 
@@ -98,6 +100,7 @@ public:
     Frame* findFrameForNavigation(const AtomicString& name, Frame& activeFrame);
     Frame* findUnsafeParentScrollPropagationBoundary();
 
+    void prepareSwapFrom(Frame*);
     void finishSwapFrom(Frame*);
 
     bool canNavigate(const Frame&);