content: Add valid handle check to ChildDiscardableSharedMemoryManager::AllocateLockedDiscardableSh…

content/child/child_discardable_shared_memory_manager.cc

 // Copyright 2014 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_discardable_shared_memory_manager.h"
 
 #include "base/memory/discardable_shared_memory.h"
 #include "base/process/process_metrics.h"
 #include "content/common/child_process_messages.h"
 
@@ skipping 169 matching lines @@
   TRACE_EVENT1("renderer",
                "ChildDiscardableSharedMemoryManager::"
                "AllocateLockedDiscardableSharedMemory",
                "size",
                size);
 
   base::SharedMemoryHandle handle = base::SharedMemory::NULLHandle();
   sender_->Send(
       new ChildProcessHostMsg_SyncAllocateLockedDiscardableSharedMemory(
           size, &handle));
+  CHECK(base::SharedMemory::IsHandleValid(handle));
   scoped_ptr<base::DiscardableSharedMemory> memory(
       new base::DiscardableSharedMemory(handle));
   CHECK(memory->Map(size));
   return memory.Pass();
 }
 
 }  // namespace content