[Download Notification] Show preview if downloaded file is image

chrome/utility/chrome_content_utility_client.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 CHROME_UTILITY_CHROME_CONTENT_UTILITY_CLIENT_H_
 #define CHROME_UTILITY_CHROME_CONTENT_UTILITY_CLIENT_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 28 matching lines @@
                                  bool shrink_to_fit,
                                  int request_id);
 
   static void set_max_ipc_message_size_for_test(int64_t max_message_size) {
     max_ipc_message_size_ = max_message_size;
   }
 
  private:
   // IPC message handlers.
   void OnUnpackWebResource(const std::string& resource_data);
+  void OnDecodeImageByHandle(const IPC::PlatformFileForTransit& image_file,
+                             bool shrink_to_fit,
+                             int request_id);
   void OnDecodeImage(const std::vector<unsigned char>& encoded_data,
                      bool shrink_to_fit,
                      int request_id);
 #if defined(OS_CHROMEOS)
   void OnRobustJPEGDecodeImage(const std::vector<unsigned char>& encoded_data,
                                int request_id);
 
   void OnCreateZipFile(const base::FilePath& src_dir,
                        const std::vector<base::FilePath>& src_relative_paths,
                        const base::FileDescriptor& dest_fd);
@@ skipping 29 matching lines @@
   bool filter_messages_;
   // A list of message_ids to filter.
   std::set<int> message_id_whitelist_;
   // Maximum IPC msg size (default to kMaximumMessageSize; override for testing)
   static int64_t max_ipc_message_size_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeContentUtilityClient);
 };
 
 #endif  // CHROME_UTILITY_CHROME_CONTENT_UTILITY_CLIENT_H_