Dart: Reorganize files

mojo/dart/embedder/test/dart_to_cpp.mojom

-// 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.
-
-[DartPackage="_mojo_for_test_only"]
-module dart_to_cpp;
-
-// This struct encompasses all of the basic types, so that they
-// may be sent from C++ to Dart and back for validation.
-struct EchoArgs {
-  int64 si64;
-  int32 si32;
-  int16 si16;
-  int8  si8;
-  uint64 ui64;
-  uint32 ui32;
-  uint16 ui16;
-  uint8  ui8;
-  float float_val;
-  float float_inf;
-  float float_nan;
-  double double_val;
-  double double_inf;
-  double double_nan;
-  string? name;
-  array<string>? string_array;
-  handle<message_pipe>? message_handle;
-  handle<data_pipe_consumer>? data_handle;
-};
-
-struct EchoArgsList {
-  EchoArgsList? next;
-  EchoArgs? item;
-};
-
-// Note: For messages which control test flow, pick numbers that are unlikely
-// to be hit as a result of our deliberate corruption of response messages.
-interface CppSide {
-  // Sent for all tests to notify that the Dart side is now ready.
-  StartTest@88888888();
-
-  // Indicates end for echo, bit-flip, and back-pointer tests.
-  TestFinished@99999999();
-
-  // Responses from specific tests.
-  PingResponse();
-  EchoResponse(EchoArgsList list);
-};
-
-interface DartSide {
-  SetClient(CppSide cppSide);
-  Ping();
-  Echo(int32 numIterations, EchoArgs arg);
-};