DocumentThreadableLoader cleanup after making sync/async paths nearly-identical.

https://chromium.googlesource.com/chromium/src/+/b5c5c86c21a0bf51cc910e0b62611aea45aa0b0d
removed most of the custom logic for sync requests from
DocumentThreadableLoader. This left a lot of helper methods with only
one caller, where previously there had been two.

* Inline HandleResponse() into ResponseReceived()
* Inline HandleReceivedData() into DataReceived()
* Inline HandleSuccessfulFinish() into NotifyFinished()
* Merge LoadRequestAsync() and LoadRequestSync() paths, and inline
  the single path into LoadRequest().

Change-Id: Ie068b49396c355884e2d71588b35280dbe07a86f
Reviewed-on: https://chromium-review.googlesource.com/1087312
Commit-Queue: Nate Chapin <japhet@chromium.org>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565404}

third_party/blink/renderer/core/loader/document_threadable_loader.h

@@ -134,19 +134,6 @@ class CORE_EXPORT DocumentThreadableLoader final : public ThreadableLoader,
   void ReportResponseReceived(unsigned long identifier,
                               const ResourceResponse&);
 
-  // Methods containing code to handle resource fetch results which are common
-  // to both sync and async mode.
-  //
-  // The FetchCredentialsMode argument must be the request's credentials mode.
-  // It's used for CORS check.
-  void HandleResponse(unsigned long identifier,
-                      network::mojom::FetchRequestMode,
-                      network::mojom::FetchCredentialsMode,
-                      const ResourceResponse&,
-                      std::unique_ptr<WebDataConsumerHandle>);
-  void HandleReceivedData(const char* data, size_t data_length);
-  void HandleSuccessfulFinish(unsigned long identifier);
-
   void DidTimeout(TimerBase*);
   // Calls the appropriate loading method according to policy and data about
   // origin. Only for handling the initial load (including fallback after
@@ -165,15 +152,12 @@ class CORE_EXPORT DocumentThreadableLoader final : public ThreadableLoader,
   // m_client.
   void HandlePreflightFailure(const KURL&, const String& error_description);
   // Investigates the response for the preflight request. If successful,
-  // the actual request will be made later in handleSuccessfulFinish().
+  // the actual request will be made later in NotifyFinished().
   void HandlePreflightResponse(const ResourceResponse&);
 
   void DispatchDidFailAccessControlCheck(const ResourceError&);
   void DispatchDidFail(const ResourceError&);
 
-  void LoadRequestAsync(const ResourceRequest&, ResourceLoaderOptions);
-  void LoadRequestSync(const ResourceRequest&, ResourceLoaderOptions);
-
   void PrepareCrossOriginRequest(ResourceRequest&) const;
 
   // This method modifies the ResourceRequest by calling