ServiceWorker: Add an API to fallback to renderer for CORS preflight

content/browser/service_worker/service_worker_url_request_job.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_URL_REQUEST_JOB_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_URL_REQUEST_JOB_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 85 matching lines @@
       ResourceType resource_type,
       RequestContextType request_context_type,
       RequestContextFrameType frame_type,
       scoped_refptr<ResourceRequestBodyImpl> body,
       ServiceWorkerFetchType fetch_type,
       Delegate* delegate);
 
   ~ServiceWorkerURLRequestJob() override;
 
   // Sets the response type.
+  // When an in-flight request possibly need CORS check, use
+  // FallbackToNetworkOrRenderer. This method will decide whether the request
+  // can directly go to the network or should fallback to a renderer to send
+  // CORS preflight. You can use FallbackToNetwork only when, like error cases,
+  // it's apparent that the request should go to the network directly.

[falken, 2016/07/07 01:11:12]

I don't understand the error case thing anymore too. The callsites of
FallbackToNetwork after this patch are:

(A) ForeignFetchRequestHandler (2)
(B) SWControlleeRequestHandler::DidLookupRegistrationForMainResource (4)

(A) makes sense because IsFallbackToRendererNeeded returns false when the event
type is FOREIGN_FETCH.
(B) makes sense because IsFallbackToRendererNeeded returns false when the
resource type is main resource.

I'm not sure error cases have anything to do with it?

[shimazu, 2016/07/07 05:02:32]

I see, I misunderstood what it's doing. Updated the comment, thanks:)

   void FallbackToNetwork();
+  void FallbackToNetworkOrRenderer();
   void ForwardToServiceWorker();
 
   bool ShouldFallbackToNetwork() const {
     return response_type_ == FALLBACK_TO_NETWORK;
   }
   bool ShouldForwardToServiceWorker() const {
     return response_type_ == FORWARD_TO_SERVICE_WORKER;
   }
 
   // net::URLRequestJob overrides:
@@ skipping 32 matching lines @@
   void OnStreamRegistered(Stream* stream) override;
 
   base::WeakPtr<ServiceWorkerURLRequestJob> GetWeakPtr();
 
  private:
   class BlobConstructionWaiter;
 
   enum ResponseType {
     NOT_DETERMINED,
     FALLBACK_TO_NETWORK,
+    FALLBACK_TO_RENDERER,  // Use this when falling back with CORS check
     FORWARD_TO_SERVICE_WORKER,
   };
 
   enum ResponseBodyType {
     UNKNOWN,
     BLOB,
     STREAM,
   };
 
   // We start processing the request if Start() is called AND response_type_
@@ skipping 23 matching lines @@
                             const std::string& status_text,
                             const ServiceWorkerHeaderMap& headers);
 
   // Creates |http_response_info_| using |http_response_headers_| and calls
   // NotifyHeadersComplete.
   void CommitResponseHeader();
 
   // Creates and commits a response header indicating error.
   void DeliverErrorResponse();
 
+  // Restarts this job to fallback to network.
+  // This can be called after StartRequest.
+  void FinalizeFallbackToNetwork();
+
+  // Sends back a response with fall_back_required set as true to trigger
+  // subsequent network requests with CORS checking.
+  // This can be called after StartRequest.
+  void FinalizeFallbackToRenderer();
+
+  // True if need to send back a response with fall_back_required set as true to
+  // trigger subsequent network requests with CORS checking.
+  bool IsFallbackToRendererNeeded() const;
+
   // For UMA.
   void SetResponseBodyType(ResponseBodyType type);
   bool ShouldRecordResult();
   void RecordResult(ServiceWorkerMetrics::URLRequestJobResult result);
   void RecordStatusZeroResponseError(
       blink::WebServiceWorkerResponseError error);
 
   // Releases the resources for streaming.
   void ClearStream();
 
@@ skipping 73 matching lines @@
   EmbeddedWorkerStatus initial_worker_status_ = EmbeddedWorkerStatus::STOPPED;
 
   base::WeakPtrFactory<ServiceWorkerURLRequestJob> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerURLRequestJob);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_URL_REQUEST_JOB_H_