Streamline frame detach

Source/core/frame/FrameHost.h

Index: Source/core/frame/FrameHost.h
diff --git a/Source/core/frame/FrameHost.h b/Source/core/frame/FrameHost.h
index d463eb048ed08a64683161b2640f8e757f3bd587..7a300784ab40ff0cdc8ef4e66e6b7c8db78c4ad3 100644
--- a/Source/core/frame/FrameHost.h
+++ b/Source/core/frame/FrameHost.h
@@ -79,12 +79,22 @@ public:
 
     void trace(Visitor*);
 
+    // Don't allow more than a certain number of frames in a page.
+    // This seems like a reasonable upper bound, and otherwise mutually
+    // recursive frameset pages can quickly bring the program to its knees
+    // with exponential growth in the number of frames.
+    static const int maxNumberOfFrames = 1000;
+    void incrementFrameCount() { ++m_frameCount; }
+    void decrementFrameCount() { ASSERT(m_frameCount); --m_frameCount; }
+    int frameCount() const;
+
 private:
     explicit FrameHost(Page&);
 
     RawPtrWillBeMember<Page> m_page;
     const OwnPtr<PinchViewport> m_pinchViewport;
     const OwnPtrWillBeMember<EventHandlerRegistry> m_eventHandlerRegistry;
+    int m_frameCount;
 };
 
 }