Make DataPipe own an impl.

mojo/edk/system/BUILD.gn

 # 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.
 
 import("../mojo_edk.gni")
 import("//testing/test.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
@@ skipping 26 matching lines @@
     "channel_info.h",
     "channel_manager.cc",
     "channel_manager.h",
     "configuration.cc",
     "configuration.h",
     "connection_manager.h",
     "core.cc",
     "core.h",
     "data_pipe.cc",
     "data_pipe.h",
+    "data_pipe_impl.h",
     "data_pipe_consumer_dispatcher.cc",
     "data_pipe_consumer_dispatcher.h",
     "data_pipe_producer_dispatcher.cc",
     "data_pipe_producer_dispatcher.h",
     "dispatcher.cc",
     "dispatcher.h",
     "endpoint_relayer.cc",
     "endpoint_relayer.h",
     "handle_signals_state.h",
     "handle_table.cc",
@@ skipping 143 matching lines @@
   deps = [
     ":system",
     ":test_utils",
     "../test:test_support",
     "//base",
     "//base/test:test_support",
     "//base/test:test_support_perf",
     "//testing/gtest",
   ]
 }