Revert of Moves mojo_js_integration_tests into blink.

third_party/WebKit/Source/core/mojo/tests/JsToCpp.mojom

-module js_to_cpp;
-
-// This struct encompasses all of the basic types, so that they
-// may be sent from C++ to JS 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;
-};
-
-interface ForTesting {};
-
-// 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 JS 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);
-
-  // Having an associated interface pointer in the message makes sure the
-  // message header version 2 is tested.
-  BitFlipResponse(EchoArgsList arg, associated ForTesting? not_used);
-
-  BackPointerResponse(EchoArgsList arg);
-};
-
-interface JsSide {
-  SetCppSide(CppSide cpp);
-
-  Ping();
-  Echo(int32 numIterations, EchoArgs arg);
-  BitFlip(EchoArgs arg);
-  BackPointer(EchoArgs arg);
-};