Always leak the Mojo parent pipe handle on child process shutdown.

mojo/edk/system/channel.h

 // Copyright 2016 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.
 
 #ifndef MOJO_EDK_SYSTEM_CHANNEL_H_
 #define MOJO_EDK_SYSTEM_CHANNEL_H_
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
@@ skipping 207 matching lines @@
   virtual void Start() = 0;
 
   // Stop processing I/O events.
   virtual void ShutDownImpl() = 0;
 
   // Queues an outgoing message on the Channel. This message will either
   // eventually be written or will fail to write and trigger
   // Delegate::OnChannelError.
   virtual void Write(MessagePtr message) = 0;
 
+  // Causes the platform handle to leak when this channel is shut down instead
+  // of closing it.
+  virtual void LeakHandle() = 0;
+
  protected:
   explicit Channel(Delegate* delegate);
   virtual ~Channel();
 
   // Called by the implementation when it wants somewhere to stick data.
   // |*buffer_capacity| may be set by the caller to indicate the desired buffer
   // size. If 0, a sane default size will be used instead.
   //
   // Returns the address of a buffer which can be written to, and indicates its
   // actual capacity in |*buffer_capacity|.
@@ skipping 41 matching lines @@
   Delegate* delegate_;
   const std::unique_ptr<ReadBuffer> read_buffer_;
 
   DISALLOW_COPY_AND_ASSIGN(Channel);
 };
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_CHANNEL_H_