Move FrameHost::m_subframeCount to Page

third_party/WebKit/Source/core/page/Page.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2013 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 213 matching lines @@
   static void allVisitedStateChanged(bool invalidateVisitedLinkHashes);
   static void visitedStateChanged(LinkHash visitedHash);
 
   void setVisibilityState(PageVisibilityState, bool);
   PageVisibilityState visibilityState() const;
   bool isPageVisible() const;
 
   bool isCursorVisible() const;
   void setIsCursorVisible(bool isVisible) { m_isCursorVisible = isVisible; }
 
+  // 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 incrementSubframeCount() { ++m_subframeCount; }
+  void decrementSubframeCount() {
+    DCHECK(m_subframeCount);

[joelhockey, 2017/03/10 00:25:43]

This is a question of chromium coding style rather than a comment.  Is this
better expressed as:

DCHECK_GT(m_subframeCount, 0);

Are either acceptable, or is there a specific preference for one over the other?

[sashab, 2017/03/10 00:56:21]

Great catch! I'd definitely say DCHECK_GT is better; changed it, thanks.

+    --m_subframeCount;
+  }
+  int subframeCount() const;
+
   void setDefaultPageScaleLimits(float minScale, float maxScale);
   void setUserAgentPageScaleConstraints(
       const PageScaleConstraints& newConstraints);
 
 #if DCHECK_IS_ON()
   void setIsPainting(bool painting) { m_isPainting = painting; }
   bool isPainting() const { return m_isPainting; }
 #endif
 
   void didCommitLoad(LocalFrame*);
@@ skipping 70 matching lines @@
   float m_deviceScaleFactor;
 
   PageVisibilityState m_visibilityState;
 
   bool m_isCursorVisible;
 
 #if DCHECK_IS_ON()
   bool m_isPainting = false;
 #endif
 
+  int m_subframeCount;
+
   // A pointer to all the interfaces provided to in-process Frames for this
   // Page.
   // FIXME: Most of the members of Page should move onto FrameHost.
   Member<FrameHost> m_frameHost;
 };
 
 extern template class CORE_EXTERN_TEMPLATE_EXPORT Supplement<Page>;
 
 }  // namespace blink
 
 #endif  // Page_h