Implement NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.

content/public/browser/navigation_handle.h

Index: content/public/browser/navigation_handle.h
diff --git a/content/public/browser/navigation_handle.h b/content/public/browser/navigation_handle.h
index 684fd26aa145b62a67505afb0e6db0e3a5ab4456..fecc77f71fc1e8adbd88874f6df2fa817aab8268 100644
--- a/content/public/browser/navigation_handle.h
+++ b/content/public/browser/navigation_handle.h
@@ -233,8 +233,10 @@ class CONTENT_EXPORT NavigationHandle {
   virtual void Resume() = 0;
 
   // Cancels a navigation that was previously deferred by a NavigationThrottle.
-  // |result| should be equal to NavigationThrottle::CANCEL or
-  // NavigationThrottle::CANCEL_AND_IGNORE.
+  // |result| should be equal to either:
+  //  - NavigationThrottle::CANCEL,
+  //  - NavigationThrottle::CANCEL_AND_IGNORE. or

[nasko, 2017/05/03 16:58:30]

nit: s/./,/

[engedy, 2017/05/05 08:23:57]

Done.

+  //  - NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.
   // Note: this may lead to the deletion of the NavigationHandle and its
   // associated NavigationThrottles.
   virtual void CancelDeferredNavigation(