[Download Notification] Show preview if downloaded file is image

chrome/common/chrome_utility_messages.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.
 
 // Multiply-included message file, so no include guard.
 
 #if defined(OS_WIN)
 #include <Windows.h>
 #endif  // defined(OS_WIN)
 
@@ skipping 117 matching lines @@
 // Tell the utility process to parse a JSON string into a Value object.
 IPC_MESSAGE_CONTROL1(ChromeUtilityMsg_ParseJSON,
                      std::string /* JSON to parse */)
 
 // Tell the utility process to decode the given image data.
 IPC_MESSAGE_CONTROL3(ChromeUtilityMsg_DecodeImage,
                      std::vector<unsigned char> /* encoded image contents */,
                      bool /* shrink image if needed for IPC msg limit */,
                      int /* delegate id */)
 
+// Tell the utility process to decode the given file.
+IPC_MESSAGE_CONTROL3(ChromeUtilityMsg_DecodeImageByHandle,
+                     IPC::PlatformFileForTransit /* image file */,
+                     bool /* shrink image if needed for IPC msg limit */,
+                     int /* delegate id */)
+
 #if defined(OS_CHROMEOS)
 // Tell the utility process to decode the given JPEG image data with a robust
 // libjpeg codec.
 IPC_MESSAGE_CONTROL2(ChromeUtilityMsg_RobustJPEGDecodeImage,
                      std::vector<unsigned char> /* encoded image contents*/,
                      int /* delegate id */)
 #endif  // defined(OS_CHROMEOS)
 
 // Tell the utility process to patch the given |input_file| using |patch_file|
 // and place the output in |output_file|. The patch should use the bsdiff
@@ skipping 132 matching lines @@
 IPC_MESSAGE_CONTROL1(ChromeUtilityHostMsg_BuildDirectWriteFontCache,
                      base::FilePath /* cache file path */)
 #endif  // defined(OS_WIN)
 
 #if defined(OS_ANDROID)
 // Reply to ChromeUtilityMsg_DetectSeccompSupport to report the level
 // of kernel support for seccomp-bpf.
 IPC_MESSAGE_CONTROL1(ChromeUtilityHostMsg_DetectSeccompSupport_ResultPrctl,
                      bool /* seccomp prctl supported */)
 #endif