Implements JS bindings for mojo data pipe.

third_party/WebKit/Source/core/mojo/MojoHandle.idl

 // Copyright 2017 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.
 
 callback MojoWatchCallback = void (MojoResult result);
 
 [
     RuntimeEnabled=MojoJS,
 ] interface MojoHandle {
     void close();
     [CallWith=ScriptState] MojoWatcher watch(MojoHandleSignals signals, MojoWatchCallback callback);
 
     // TODO(alokp): Create MessagePipeHandle, a subclass of MojoHandle
     // and move the following member functions.
     MojoResult writeMessage(BufferSource buffer, sequence<MojoHandle> handles);
     MojoReadMessageResult readMessage(optional MojoReadMessageFlags flags);
 
+    // TODO(alokp): Create DataPipeHandle, a subclass of MojoHandle

[jbroman, 2017/03/07 20:31:47]

If you do this, wouldn't it be a MojoDataPipeProducerHandle and a
MojoDataPipeConsumerHandle? IIUC each handle can only be used for one set of
operations.

[alokp, 2017/03/07 20:49:32]

Ah yes - updated comment.

+    // and move the following member functions.
+    MojoWriteDataResult writeData(BufferSource buffer, optional MojoWriteDataOptions options);
+    MojoReadDataResult queryData();
+    MojoReadDataResult discardData(unsigned long numBytes, optional MojoDiscardDataOptions options);
+    MojoReadDataResult readData(unsigned long numBytes, BufferSource buffer, optional MojoReadDataOptions options);
+
     // TODO(alokp): Create SharedBufferHandle, a subclass of MojoHandle
     // and move the following member functions.
     MojoMapBufferResult mapBuffer(unsigned long offset, unsigned long numBytes);
     MojoCreateSharedBufferResult duplicateBufferHandle(optional MojoDuplicateBufferHandleOptions options);
 };