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

content/browser/service_worker/service_worker_url_request_job.h

Index: content/browser/service_worker/service_worker_url_request_job.h
diff --git a/content/browser/service_worker/service_worker_url_request_job.h b/content/browser/service_worker/service_worker_url_request_job.h
index 029871bed969260948766f54e73c318123c609b3..c69a9cfe1c4c532d43082b4c6bd975bd01db3187 100644
--- a/content/browser/service_worker/service_worker_url_request_job.h
+++ b/content/browser/service_worker/service_worker_url_request_job.h
@@ -103,7 +103,13 @@ class CONTENT_EXPORT ServiceWorkerURLRequestJob
   ~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 it's apparent that
+  // the request should go to the network directly.

[falken, 2016/07/05 06:49:28]

Reading this makes me feel there should just be one Fallback*() function. Is it
really worth splitting into two functions? I see patch set 1 originally just had
one function.

[shimazu, 2016/07/06 06:27:35]

Replied to the patch set 1

   void FallbackToNetwork();
+  void FallbackToNetworkOrRenderer();
   void ForwardToServiceWorker();
 
   bool ShouldFallbackToNetwork() const {
@@ -156,6 +162,7 @@ class CONTENT_EXPORT ServiceWorkerURLRequestJob
   enum ResponseType {
     NOT_DETERMINED,
     FALLBACK_TO_NETWORK,
+    FALLBACK_TO_RENDERER,  // Use this when falling back with CORS check
     FORWARD_TO_SERVICE_WORKER,
   };
 
@@ -199,6 +206,19 @@ class CONTENT_EXPORT ServiceWorkerURLRequestJob
   // 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();