Use mime type for image extension

components/image_fetcher/image_data_fetcher.cc

 // Copyright 2016 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.
 
 #include "components/image_fetcher/image_data_fetcher.h"
 
 #include "net/base/load_flags.h"
+#include "net/http/http_response_headers.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "net/url_request/url_request_status.h"
 #include "url/gurl.h"
 
 using data_use_measurement::DataUseUserData;
 
 namespace image_fetcher {
 
@@ skipping 52 matching lines @@
   request->url_fetcher->SetReferrerPolicy(referrer_policy);
   request->url_fetcher->Start();
 
   pending_requests_[request->url_fetcher.get()] = std::move(request);
 }
 
 void ImageDataFetcher::OnURLFetchComplete(const net::URLFetcher* source) {
   auto request_iter = pending_requests_.find(source);
   DCHECK(request_iter != pending_requests_.end());
 
+  std::string mime_type;
+  if (source->GetResponseHeaders()) {
+    source->GetResponseHeaders()->GetMimeType(&mime_type);

[Marc Treib, 2017/02/09 13:49:47]

You could read directly into &metadata.mime_type

[gambard, 2017/02/09 15:10:32]

Done.

+  }
+
+  RequestMetadata metadata;
+  metadata.mime_type = mime_type;
+
   std::string image_data;
   if (source->GetStatus().status() == net::URLRequestStatus::SUCCESS) {
     source->GetResponseAsString(&image_data);
   }
-  request_iter->second->callback.Run(image_data);
+  request_iter->second->callback.Run(image_data, metadata);
 
   // Remove the finished request.
   pending_requests_.erase(request_iter);
 }
 
 }  // namespace image_fetcher