Allow navigations to frames that aren't being unloaded in the unload handler.

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

Index: third_party/WebKit/Source/core/loader/NavigationScheduler.h
diff --git a/third_party/WebKit/Source/core/loader/NavigationScheduler.h b/third_party/WebKit/Source/core/loader/NavigationScheduler.h
index b6ac577ef29e1910bd273b513f874287048c0a8a..5f24153e23afa77131fc180979795e904efe26fd 100644
--- a/third_party/WebKit/Source/core/loader/NavigationScheduler.h
+++ b/third_party/WebKit/Source/core/loader/NavigationScheduler.h
@@ -96,22 +96,6 @@ class CORE_EXPORT NavigationScheduler final
   WebScheduler::NavigatingFrameType m_frameType;
 };
 
-class NavigationDisablerForUnload {
-  WTF_MAKE_NONCOPYABLE(NavigationDisablerForUnload);
-  STACK_ALLOCATED();
-
- public:
-  NavigationDisablerForUnload() { s_navigationDisableCount++; }
-  ~NavigationDisablerForUnload() {
-    DCHECK(s_navigationDisableCount);
-    s_navigationDisableCount--;
-  }
-  static bool isNavigationAllowed() { return !s_navigationDisableCount; }
-
- private:
-  static unsigned s_navigationDisableCount;
-};
-
 }  // namespace blink
 
 #endif  // NavigationScheduler_h