Centralize the setting of Accept headers

content/browser/loader/mime_type_resource_handler.h

 // Copyright (c) 2012 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_LOADER_MIME_TYPE_RESOURCE_HANDLER_H_
 #define CONTENT_BROWSER_LOADER_MIME_TYPE_RESOURCE_HANDLER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 15 matching lines @@
 // ResourceHandler that, if necessary, buffers a response body without passing
 // it to the next ResourceHandler until it can perform mime sniffing on it.
 // Once a response's MIME type is known, initiates special handling of the
 // response if needed (starts downloads, sends data to some plugin types via a
 // special channel).
 //
 // Uses the buffer provided by the original event handler for buffering, and
 // continues to reuses it until it can determine the MIME type
 // subsequent reads until it's done buffering.  As a result, the buffer
 // returned by the next ResourceHandler must have a capacity of at least
 // net::kMaxBytesToSniff * 2.

[mmenke, 2016/04/01 15:29:08]

Think it's worth mentioning its new job of setting Accept header based on
ResourceType in another paragraph.

[Nate Chapin, 2016/04/01 19:01:24]

Done.

 class CONTENT_EXPORT MimeTypeResourceHandler
     : public LayeredResourceHandler,
       public ResourceController {
  public:
   // If ENABLE_PLUGINS is defined, |plugin_service| must not be NULL.
   MimeTypeResourceHandler(scoped_ptr<ResourceHandler> next_handler,
                           ResourceDispatcherHostImpl* host,
                           PluginService* plugin_service,
                           net::URLRequest* request);
   ~MimeTypeResourceHandler() override;
 
  private:
   // ResourceHandler implementation:
   void SetController(ResourceController* controller) override;
   bool OnResponseStarted(ResourceResponse* response, bool* defer) override;
+  bool OnWillStart(const GURL&, bool* defer) override;
   bool OnWillRead(scoped_refptr<net::IOBuffer>* buf,
                   int* buf_size,
                   int min_size) override;
   bool OnReadCompleted(int bytes_read, bool* defer) override;
   void OnResponseCompleted(const net::URLRequestStatus& status,
                            const std::string& security_info,
                            bool* defer) override;
 
   // ResourceController implementation:
   void Resume() override;
@@ skipping 62 matching lines @@
   bool must_download_is_set_;
 
   base::WeakPtrFactory<MimeTypeResourceHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MimeTypeResourceHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_LOADER_MIME_TYPE_RESOURCE_HANDLER_H_