Revert of Teach navigation throttles how to cancel requests in WillProcessResponse.

content/public/browser/navigation_throttle.h

Index: content/public/browser/navigation_throttle.h
diff --git a/content/public/browser/navigation_throttle.h b/content/public/browser/navigation_throttle.h
index 5876343db0decd9bb6933f6243299aa81b825d06..fff64b1f4fb8c61f425c27b140786fce5eaa617d 100644
--- a/content/public/browser/navigation_throttle.h
+++ b/content/public/browser/navigation_throttle.h
@@ -55,15 +55,6 @@
   // CANCEL_AND_IGNORE or DEFER and perform the destruction asynchronously.
   virtual ThrottleCheckResult WillRedirectRequest();
 
-  // Called when a response's headers and metadata are available.
-  //
-  // The implementer is responsible for ensuring that the WebContents this
-  // throttle is associated with remain alive during the duration of this
-  // method. Failing to do so will result in use-after-free bugs. Should the
-  // implementer need to destroy the WebContents, it should return CANCEL,
-  // CANCEL_AND_IGNORE and perform the destruction asynchronously.
-  virtual ThrottleCheckResult WillProcessResponse();
-
   // The NavigationHandle that is tracking the information related to this
   // navigation.
   NavigationHandle* navigation_handle() const { return navigation_handle_; }