Turn the utility process image decoder into a Mojo service.

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 24 matching lines @@
   // Shared with extensions::ExtensionsHandler.
   static SkBitmap DecodeImage(const std::vector<unsigned char>& encoded_data,
                               bool shrink_to_fit);
   static void DecodeImageAndSend(const std::vector<unsigned char>& encoded_data,
                                  bool shrink_to_fit);
 
   static void set_max_ipc_message_size_for_test(int64_t max_message_size) {
     max_ipc_message_size_ = max_message_size;
   }
 
+  // Reference counting for Mojo services. A reference count is incremented when
+  // Mojo services are connected to, and decremented when the connection is
+  // destroyed. When the count reaches 0, this process is freed. The assumption
+  // is that multiple Mojo services can be connected to in the same utility
+  // process. This is a Mojo alternative to "batch mode" for Chrome IPC.
+  void MojoRef();
+  void MojoUnref();
+
  private:
   // IPC message handlers.
   void OnUnpackWebResource(const std::string& resource_data);
   void OnDecodeImage(const std::vector<unsigned char>& encoded_data,
                      bool shrink_to_fit);
   void OnRobustJPEGDecodeImage(
       const std::vector<unsigned char>& encoded_data);
 
 #if defined(OS_CHROMEOS)
   void OnCreateZipFile(const base::FilePath& src_dir,
@@ skipping 22 matching lines @@
   typedef ScopedVector<UtilityMessageHandler> Handlers;
   Handlers handlers_;
 
   // Flag to enable whitelisting.
   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_;
 
+  int32_t mojo_service_ref_count_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeContentUtilityClient);
 };
 
 #endif  // CHROME_UTILITY_CHROME_CONTENT_UTILITY_CLIENT_H_