Mac: Ensure that Mach messages always get a reply

content/child/child_io_surface_manager_mac.cc

 // Copyright 2015 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 "content/child/child_io_surface_manager_mac.h"
 
 #include "base/mac/mach_logging.h"
 #include "content/common/mac/io_surface_manager_messages.h"
 
 namespace content {
@@ skipping 111 matching lines @@
   memcpy(data.request.token_name, token_.name, sizeof(token_.name));
 
   kr = mach_msg(&data.request.header, MACH_SEND_MSG | MACH_RCV_MSG,
                 sizeof(data.request), sizeof(data.reply), reply_port,
                 MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
   if (kr != KERN_SUCCESS) {
     MACH_LOG(ERROR, kr) << "mach_msg";
     return nullptr;
   }
 
+  // Crash the renderer (for now) to see if this was the cause of renderer hangs
+  // that have recently been noticed.
+  // http://crbug.com/532149
+  CHECK(data.reply.msg.result);
+  if (!data.reply.msg.result) {

[reveman, 2015/09/18 18:22:30]

nit: this if-statement seems unnecessary with the check above

[ccameron, 2015/09/18 18:36:00]

Removed for now.

+    LOG(ERROR) << "AcquireIOSurface returned failure!";
+    return nullptr;
+  }
+
   // Deallocate the right after creating an IOSurface reference.
   base::mac::ScopedMachSendRight scoped_io_surface_right(
       data.reply.msg.io_surface_port.name);
 
   return IOSurfaceLookupFromMachPort(scoped_io_surface_right);
 }
 
 ChildIOSurfaceManager::ChildIOSurfaceManager() {}
 
 ChildIOSurfaceManager::~ChildIOSurfaceManager() {}
 
 }  // namespace content