Convert utility process ImageWriter IPC to mojo

chrome/utility/chrome_content_utility_client.h

Index: chrome/utility/chrome_content_utility_client.h
diff --git a/chrome/utility/chrome_content_utility_client.h b/chrome/utility/chrome_content_utility_client.h
index d24f0b11b7c7f03562a27a93f9a59857e66089fa..0a659e18651a501b58be64fc69c68e857fa274f7 100644
--- a/chrome/utility/chrome_content_utility_client.h
+++ b/chrome/utility/chrome_content_utility_client.h
@@ -63,10 +63,7 @@ class ChromeContentUtilityClient : public content::ContentUtilityClient {
   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_;
+  bool utility_process_running_elevated_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeContentUtilityClient);
 };