Disable navigations in the unload handler.

third_party/WebKit/Source/core/loader/NavigationScheduler.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2009 Adam Barth. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 91 matching lines @@
     {
         ASSERT(s_navigationDisableCount);
         s_navigationDisableCount--;
     }
     static bool isNavigationAllowed() { return !s_navigationDisableCount; }
 
 private:
     static unsigned s_navigationDisableCount;
 };
 
-class CORE_EXPORT NavigationCounterForUnload {
-    WTF_MAKE_NONCOPYABLE(NavigationCounterForUnload);
+class CORE_EXPORT NavigationDisablerForUnload {

[dcheng, 2016/08/16 22:32:03]

Can we just use NavigationDisablerForBeforeUnload, but rename it?

+    WTF_MAKE_NONCOPYABLE(NavigationDisablerForUnload);
     STACK_ALLOCATED();
 public:
-    NavigationCounterForUnload()
+    NavigationDisablerForUnload()
     {
         s_inUnloadHandler++;
     }
-    ~NavigationCounterForUnload()
+    ~NavigationDisablerForUnload()
     {
         DCHECK(s_inUnloadHandler);
         s_inUnloadHandler--;
     }
     static bool inUnloadHandler() { return !!s_inUnloadHandler; }
 
 private:
     static unsigned s_inUnloadHandler;
 };
 
 } // namespace blink
 
 #endif // NavigationScheduler_h