Disable native messaging in non-supported configurations

chrome/browser/extensions/api/messaging/message_service.cc

 // 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.
 
 #include "chrome/browser/extensions/api/messaging/message_service.h"
 
 #include "base/atomic_sequence_num.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/json/json_writer.h"
@@ skipping 170 matching lines @@
 
   OpenChannelImpl(scoped_ptr<OpenChannelParams>(params));
 }
 
 void MessageService::OpenChannelToNativeApp(
     int source_process_id,
     int source_routing_id,
     int receiver_port_id,
     const std::string& source_extension_id,
     const std::string& native_app_name) {
+#if defined(OS_WIN) || defined(OS_MAXOSX) || defined(OS_LINUX)
   content::RenderProcessHost* source =
       content::RenderProcessHost::FromID(source_process_id);
   if (!source)
     return;
 
   WebContents* source_contents = tab_util::GetWebContentsByID(
       source_process_id, source_routing_id);
 
   // Include info about the opener's tab (if it was a tab).
   std::string tab_json = "null";
   if (source_contents) {
     scoped_ptr<DictionaryValue> tab_value(ExtensionTabUtil::CreateTabValue(
         source_contents));
     base::JSONWriter::Write(tab_value.get(), &tab_json);
   }
 
   scoped_ptr<MessageChannel> channel(new MessageChannel());
   channel->opener.reset(new ExtensionMessagePort(source, MSG_ROUTING_CONTROL,
                                                  source_extension_id));
 
   scoped_ptr<NativeMessageProcessHost> native_process =
       NativeMessageProcessHost::Create(
           base::WeakPtr<NativeMessageProcessHost::Client>(
               weak_factory_.GetWeakPtr()),
           native_app_name, receiver_port_id);
 
   // Abandon the channel
   if (!native_process.get()) {
     LOG(ERROR) << "Failed to create native process.";
+    // Treat it as a disconnect.
+    ExtensionMessagePort port(source, MSG_ROUTING_CONTROL, "");
+    port.DispatchOnDisconnect(GET_OPPOSITE_PORT_ID(receiver_port_id), true);
     return;
   }
   channel->receiver.reset(new NativeMessagePort(native_process.release()));
 
   // Keep the opener alive until the channel is closed.
   channel->opener->IncrementLazyKeepaliveCount();
 
   AddChannel(channel.release(), receiver_port_id);
+#else  // defined(OS_WIN) || defined(OS_MAXOSX) || defined(OS_LINUX)
+  ExtensionMessagePort port(source, MSG_ROUTING_CONTROL, "");
+  port.DispatchOnDisconnect(GET_OPPOSITE_PORT_ID(receiver_port_id), true);
+#endif  // !(defined(OS_WIN) || defined(OS_MAXOSX) || defined(OS_LINUX))

[Matt Perry, 2013/02/11 22:44:54]

nit: These comments seem backwards to me. The endif comment is actually matches
the else branch's condition. If anything should be labeled with the else
branch's condition, it should be the else branch itself.

[Sergey Ulanov, 2013/02/13 01:15:25]

Done.

 }
 
 void MessageService::OpenChannelToTab(
     int source_process_id, int source_routing_id, int receiver_port_id,
     int tab_id, const std::string& extension_id,
     const std::string& channel_name) {
   content::RenderProcessHost* source =
       content::RenderProcessHost::FromID(source_process_id);
   if (!source)
     return;
@@ skipping 237 matching lines @@
     return;
 
   params->source = source;
   params->receiver.reset(new ExtensionMessagePort(host->render_process_host(),
                                                   MSG_ROUTING_CONTROL,
                                                   params->target_extension_id));
   OpenChannelImpl(params.Pass());
 }
 
 }  // namespace extensions