components/image_fetcher: Expose RequestMetadata from ImageFetcher

components/image_fetcher/image_fetcher_impl.cc

 // 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.
 
 #include "components/image_fetcher/image_fetcher_impl.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "net/base/load_flags.h"
@@ skipping 28 matching lines @@
   image_data_fetcher_->SetDataUseServiceName(data_use_service_name);
 }
 
 void ImageFetcherImpl::SetDesiredImageFrameSize(const gfx::Size& size) {
   desired_image_frame_size_ = size;
 }
 
 void ImageFetcherImpl::StartOrQueueNetworkRequest(
     const std::string& id,
     const GURL& image_url,
-    base::Callback<void(const std::string&, const gfx::Image&)> callback) {
+    const ImageFetcherCallback& callback) {
   // Before starting to fetch the image. Look for a request in progress for
   // |image_url|, and queue if appropriate.
   ImageRequestMap::iterator it = pending_net_requests_.find(image_url);
   if (it == pending_net_requests_.end()) {
     ImageRequest request;
     request.id = id;
     request.callbacks.push_back(callback);
     pending_net_requests_[image_url].swap(&request);
 
     image_data_fetcher_->FetchImageData(
         image_url,
         base::Bind(&ImageFetcherImpl::OnImageURLFetched,
                    base::Unretained(this), image_url));
   } else {
     // Request in progress. Register as an interested callback.
     it->second.callbacks.push_back(callback);
   }
 }
 
 void ImageFetcherImpl::OnImageURLFetched(const GURL& image_url,
                                          const std::string& image_data,
                                          const RequestMetadata& metadata) {
   // Inform the ImageFetcherDelegate.
   if (delegate_) {
     auto it = pending_net_requests_.find(image_url);
     DCHECK(it != pending_net_requests_.end());
     delegate_->OnImageDataFetched(it->second.id, image_data);
   }
 
-  image_decoder_->DecodeImage(image_data, desired_image_frame_size_,
-                              base::Bind(&ImageFetcherImpl::OnImageDecoded,
-                                         base::Unretained(this), image_url));
+  image_decoder_->DecodeImage(
+      image_data, desired_image_frame_size_,
+      base::Bind(&ImageFetcherImpl::OnImageDecoded, base::Unretained(this),
+                 image_url, metadata));
 }
 
 void ImageFetcherImpl::OnImageDecoded(const GURL& image_url,
+                                      const RequestMetadata& metadata,
                                       const gfx::Image& image) {
   // Get request for the given image_url from the request queue.
   ImageRequestMap::iterator image_iter = pending_net_requests_.find(image_url);
   DCHECK(image_iter != pending_net_requests_.end());
   ImageRequest* request = &image_iter->second;
 
   // Run all callbacks
   for (const auto& callback : request->callbacks) {
-    callback.Run(request->id, image);
+    callback.Run(request->id, image, metadata);

[jkrcal, 2017/03/20 10:49:59]

nit: I do not like the order of args being inconsistent. I see why this private
function needs this order. Is there a reason for the callback having the order
the other way around?

[Marc Treib, 2017/03/20 10:56:08]

The order in the callback is consistent with the corresponding callback in
ImageDataFetcher:
https://cs.chromium.org/chromium/src/components/image_fetcher/image_data_fetc...

I think this order makes more sense: First the actual result (image), then the
extra info. It's unfortunate that the private function needs things in a
different order, but that should have no influence on the public API.

[jkrcal, 2017/03/20 11:02:19]

Ok, makes sense. lgtm

   }
 
   // Inform the ImageFetcherDelegate.
   if (delegate_) {
     delegate_->OnImageFetched(request->id, image);
   }
 
   // Erase the completed ImageRequest.
   pending_net_requests_.erase(image_iter);
 }
 
 ImageDecoder* ImageFetcherImpl::GetImageDecoder() {
   return image_decoder_.get();
 }
 
 }  // namespace image_fetcher