Use mime type for image extension

ios/web/public/image_fetcher/image_data_fetcher.mm

 // Copyright 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.
 
 #import "ios/web/public/image_fetcher/image_data_fetcher.h"
 
 #import <Foundation/Foundation.h>
 #include <stddef.h>
 
 #include "base/bind.h"
@@ skipping 64 matching lines @@
   DCHECK(task_runner_.get());
 }
 
 ImageDataFetcher::~ImageDataFetcher() {
   // Delete all the entries in the |downloads_in_progress_| map.  This will in
   // turn cancel all of the requests.
   for (const auto& pair : downloads_in_progress_) {
     delete pair.first;
   }
 }
-
 void ImageDataFetcher::StartDownload(
     const GURL& url,
     ImageFetchedCallback callback,
     const std::string& referrer,
     net::URLRequest::ReferrerPolicy referrer_policy) {
+  StartDownloadWithMime(url,
+                        ^(const GURL& url, int http_response_code,
+                          const std::string& mime_type, NSData* data) {
+                          callback(url, http_response_code, data);
+                        },
+                        referrer, referrer_policy);
+}
+
+void ImageDataFetcher::StartDownloadWithMime(
+    const GURL& url,
+    ImageFetchedCallbackWithMime callback,
+    const std::string& referrer,
+    net::URLRequest::ReferrerPolicy referrer_policy) {
   DCHECK(request_context_getter_.get());
   net::URLFetcher* fetcher =
       net::URLFetcher::Create(url, net::URLFetcher::GET, this).release();
   downloads_in_progress_[fetcher] = [callback copy];
   fetcher->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
                         net::LOAD_DO_NOT_SAVE_COOKIES |
                         net::LOAD_DO_NOT_SEND_AUTH_DATA);
   fetcher->SetRequestContext(request_context_getter_.get());
   fetcher->SetReferrer(referrer);
   fetcher->SetReferrerPolicy(referrer_policy);
@@ skipping 13 matching lines @@
   if (downloads_in_progress_.find(fetcher) == downloads_in_progress_.end()) {
     LOG(ERROR) << "Received callback for unknown URLFetcher " << fetcher;
     return;
   }
 
   // Ensures that |fetcher| will be deleted in the event of early return.
   std::unique_ptr<const net::URLFetcher> fetcher_deleter(fetcher);
 
   // Retrieves the callback and ensures that it will be deleted in the event
   // of early return.
-  base::mac::ScopedBlock<ImageFetchedCallback> callback(
+  base::mac::ScopedBlock<ImageFetchedCallbackWithMime> callback(
       downloads_in_progress_[fetcher]);
 
   // Remove |fetcher| from the map.
   downloads_in_progress_.erase(fetcher);
 
   // Make sure the request was successful. For "data" requests, the response
   // code has no meaning, because there is no actual server (data is encoded
   // directly in the URL). In that case, set the response code to 200 (OK).
   const GURL& original_url = fetcher->GetOriginalURL();
   const int http_response_code =
       original_url.SchemeIs("data") ? 200 : fetcher->GetResponseCode();
   if (http_response_code != 200) {
-    (callback.get())(original_url, http_response_code, nil);
+    (callback.get())(original_url, http_response_code, std::string(), nil);
     return;
   }
 
   std::string response;
   if (!fetcher->GetResponseAsString(&response)) {
-    (callback.get())(original_url, http_response_code, nil);
+    (callback.get())(original_url, http_response_code, std::string(), nil);
     return;
   }
 
   // Create a NSData from the returned data and notify the callback.
   base::scoped_nsobject<NSData> data([[NSData alloc]
       initWithBytes:reinterpret_cast<const unsigned char*>(response.data())
              length:response.size()]);
 
+  std::string mime_type;
   if (fetcher->GetResponseHeaders()) {
-    std::string mime_type;
     fetcher->GetResponseHeaders()->GetMimeType(&mime_type);
     if (mime_type == kWEBPMimeType) {
       base::PostTaskAndReplyWithResult(
           task_runner_.get(), FROM_HERE, base::Bind(&DecodeWebpImage, data),
           base::Bind(&ImageDataFetcher::RunCallback, weak_factory_.GetWeakPtr(),
-                     callback, original_url, http_response_code));
+                     callback, original_url, http_response_code, mime_type));
       return;
     }
   }
-  (callback.get())(original_url, http_response_code, data);
+  (callback.get())(original_url, http_response_code, mime_type, data);
 }
 
 void ImageDataFetcher::RunCallback(
-    const base::mac::ScopedBlock<ImageFetchedCallback>& callback,
+    const base::mac::ScopedBlock<ImageFetchedCallbackWithMime>& callback,
     const GURL& url,
     int http_response_code,
+    const std::string& mime_type,
     NSData* data) {
-  (callback.get())(url, http_response_code, data);
+  (callback.get())(url, http_response_code, mime_type, data);
 }
 
 void ImageDataFetcher::SetRequestContextGetter(
     const scoped_refptr<net::URLRequestContextGetter>& request_context_getter) {
   request_context_getter_ = request_context_getter;
 }
 
 }  // namespace web