Teach navigation throttles how to cancel requests in WillProcessResponse.

content/browser/frame_host/navigation_request.h

Index: content/browser/frame_host/navigation_request.h
diff --git a/content/browser/frame_host/navigation_request.h b/content/browser/frame_host/navigation_request.h
index fb418c54d11cc7184f8af1fc1602198a88a326f7..ed2a7d3c51d8fc6a5298ca36cbe253ba5aa8b467 100644
--- a/content/browser/frame_host/navigation_request.h
+++ b/content/browser/frame_host/navigation_request.h
@@ -161,6 +161,7 @@ class CONTENT_EXPORT NavigationRequest : public NavigationURLLoaderDelegate {
   // NavigationHandle.
   void OnStartChecksComplete(NavigationThrottle::ThrottleCheckResult result);
   void OnRedirectChecksComplete(NavigationThrottle::ThrottleCheckResult result);
+  void OnResponseChecksComplete(NavigationThrottle::ThrottleCheckResult result);

[clamy, 2016/01/25 16:36:21]

Let's remove the PlzNavigate changes since I'll be working on those.
NavigationRequest is a PlzNavigate specific file, so it should not be modified.

[Mike West, 2016/01/26 09:41:41]

Done.

 
   // Called when the navigation is about to be sent to the IO thread.
   void InitializeServiceWorkerHandleIfNeeded();
@@ -183,6 +184,10 @@ class CONTENT_EXPORT NavigationRequest : public NavigationURLLoaderDelegate {
 
   NavigationState state_;
 
+  // Used to store response information during throttle checks in
+  // OnResponseStarted.
+  scoped_refptr<ResourceResponse> response_;
+  scoped_ptr<StreamHandle> body_;
 
   // The parameters to send to the IO thread. |loader_| takes ownership of
   // |info_| after calling BeginNavigation.