Fix leak of PlatformHandleDispatchers in Mojo IPC

ipc/mojo/ipc_mojo_handle_attachment.cc

 // Copyright (c) 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 "ipc/mojo/ipc_mojo_handle_attachment.h"
 
 #include "ipc/ipc_message_attachment_set.h"
 #include "third_party/mojo/src/mojo/edk/embedder/embedder.h"
 
 namespace IPC {
 namespace internal {
 
 MojoHandleAttachment::MojoHandleAttachment(mojo::ScopedHandle handle)
     : handle_(handle.Pass()) {
 }
 
 MojoHandleAttachment::~MojoHandleAttachment() {
 }
 
 MessageAttachment::Type MojoHandleAttachment::GetType() const {
   return TYPE_MOJO_HANDLE;
 }
 
 #if defined(OS_POSIX)
 base::PlatformFile MojoHandleAttachment::TakePlatformFile() {
   mojo::embedder::ScopedPlatformHandle platform_handle;
   MojoResult unwrap_result = mojo::embedder::PassWrappedPlatformHandle(
-      handle_.release().value(), &platform_handle);
+      handle_.get().value(), &platform_handle);
+  handle_.reset();
   if (unwrap_result != MOJO_RESULT_OK) {
     LOG(ERROR) << "Pipe failed to covert handles. Closing: " << unwrap_result;
     return -1;
   }
 
   return platform_handle.release().fd;
 }
 #endif  // OS_POSIX
 
 mojo::ScopedHandle MojoHandleAttachment::TakeHandle() {
   return handle_.Pass();
 }
 
 }  // namespace internal
 }  // namespace IPC