Load NPAPI plugin resources through the browser process directly instead of going through the render

content/common/resource_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.
 
 // IPC messages for resource loading.
 //
 // NOTE: All messages must send an |int request_id| as their first parameter.
 
 // Multiply-included message file, hence no include guard.
 #include "base/memory/shared_memory.h"
@@ skipping 130 matching lines @@
   IPC_STRUCT_MEMBER(WebKit::WebReferrerPolicy, referrer_policy)
 
   // Additional HTTP request headers.
   IPC_STRUCT_MEMBER(std::string, headers)
 
   // net::URLRequest load flags (0 by default).
   IPC_STRUCT_MEMBER(int, load_flags)
 
   // Process ID from which this request originated, or zero if it originated
   // in the renderer itself.
+  // If kDirectNPAPIRequests isn't specified, then plugin requests get routed
+  // through the renderer and and this holds the pid of the plugin process.
+  // Otherwise this holds the render_process_id of the view that has the plugin.
   IPC_STRUCT_MEMBER(int, origin_pid)
 
   // What this resource load is for (main frame, sub-frame, sub-resource,
   // object).
   IPC_STRUCT_MEMBER(ResourceType::Type, resource_type)
 
   // The priority of this request.
   IPC_STRUCT_MEMBER(net::RequestPriority, priority)
 
   // Used by plugin->browser requests to get the correct net::URLRequestContext.
@@ skipping 146 matching lines @@
                      int /* request_id */)
 
 // Sent when the renderer process deletes a resource loader.
 IPC_MESSAGE_CONTROL1(ResourceHostMsg_ReleaseDownloadedFile,
                      int /* request_id */)
 
 // Sent by the renderer when a resource request changes priority.
 IPC_MESSAGE_CONTROL2(ResourceHostMsg_DidChangePriority,
                      int /* request_id */,
                      net::RequestPriority)