Add interface versioning. Methods queryVersion and requireVersion.

mojo/public/js/lib/control_message_proxy.js

Index: mojo/public/js/lib/control_message_proxy.js
diff --git a/mojo/public/js/lib/control_message_proxy.js b/mojo/public/js/lib/control_message_proxy.js
new file mode 100644
index 0000000000000000000000000000000000000000..1dd461482c6feaf86382d57e8bf6600733dc50f6
--- /dev/null
+++ b/mojo/public/js/lib/control_message_proxy.js
@@ -0,0 +1,97 @@
+// 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.
+
+define("mojo/public/js/lib/control_message_proxy", [
+  "mojo/public/interfaces/bindings/interface_control_messages.mojom",
+  "mojo/public/js/validator",

[yzshen1, 2017/02/11 01:11:29]

Alphabetically, please.

[wangjimmy, 2017/02/13 20:43:07]

Done.

+  "mojo/public/js/codec",
+], function(interfaceCtrlMsgs, validator, codec) {

[yzshen1, 2017/02/11 01:11:29]

interfaceCtrlMsgs -> controlMessages?

[wangjimmy, 2017/02/13 20:43:07]

Done.

+
+  var Validator = validator.Validator;
+
+  function sendRunOrClosePipeMessage(receiver, runOrClosePipeMsgParams) {
+    var messageName = interfaceCtrlMsgs.kRunOrClosePipeMessageId;
+    var payloadSize = interfaceCtrlMsgs.RunOrClosePipeMessageParams
+                                              .encodedSize;
+    var builder = new codec.MessageBuilder(messageName, payloadSize);
+    builder.encodeStruct(interfaceCtrlMsgs.RunOrClosePipeMessageParams,
+                         runOrClosePipeMsgParams);
+    var message = builder.finish();
+    receiver.accept(message);
+  }
+
+  function validateControlResponse(message) {
+    var messageValidator = new Validator(message);
+    var error = messageValidator.validateMessageIsResponse();
+    if (error != validator.validationError.NONE) {
+      throw error;
+    }
+
+    if (!message.getName() &&

[yzshen1, 2017/02/11 01:11:29]

Do we need this check at all?

[wangjimmy, 2017/02/13 20:43:07]

Done.

+        message.getName() != interfaceCtrlMsgs.kRunMessageId) {
+      throw new Error('Control message name is not kRunMessageId');

[yzshen1, 2017/02/11 01:11:29]

Please consider using double quotes.

And we need to validate the payload as well.

[wangjimmy, 2017/02/13 20:43:07]

Done.

+    }
+  }
+
+  function accept(message) {

[yzshen1, 2017/02/11 01:11:29]

Could we give it a more descriptive name? We have too many methods named accept.
:)

[wangjimmy, 2017/02/13 20:43:07]

Done.

+    validateControlResponse(message);
+
+    var reader = new codec.MessageReader(message);
+    var runResponseMessageParams = reader.decodeStruct(
+        interfaceCtrlMsgs.RunResponseMessageParams);
+
+    return Promise.resolve(runResponseMessageParams);
+  }
+
+ /**
+  * Sends the given run message through the receiver.
+  * Accept the response message from the receiver and decode
+  * the message struct to RunResponseMessageParams.
+  * .
+  * @param  {Router} receiver.
+  * @param  {RunMessageParams} runMessageParams to be sent via a message.
+  * @return {Promise} that resolves to a RunResponseMessageParams.
+  */
+  function sendRunMessage(receiver, runMsgParams) {
+    var messageName = interfaceCtrlMsgs.kRunMessageId;
+    var payloadSize = interfaceCtrlMsgs.RunMessageParams.encodedSize;
+    // requestID is set to 0, but is later

[yzshen1, 2017/02/11 01:11:29]

Please fill this line to as close to 80 chars as possible.

[wangjimmy, 2017/02/13 20:43:07]

Done.

+    // properly set by Router's acceptAndExpectResponse

[yzshen1, 2017/02/11 01:11:29]

Usually in comments, we use xxx() to indicate function names and |xxx| to
indicate variables.

Comments should be sentence with trailing "."

[wangjimmy, 2017/02/13 20:43:07]

Done.

+    var builder = new codec.MessageWithRequestIDBuilder(messageName,
+      payloadSize, codec.kMessageExpectsResponse, 0);
+    builder.encodeStruct(interfaceCtrlMsgs.RunMessageParams, runMsgParams);
+    var message = builder.finish();
+
+    return receiver.acceptAndExpectResponse(message).then(accept);
+  }
+
+  function ControlMessageProxy() {
+    this.receiver = null;
+  }
+
+  ControlMessageProxy.prototype.queryVersion = function() {
+    var runMsgParams = new interfaceCtrlMsgs.RunMessageParams();
+    runMsgParams.input = new interfaceCtrlMsgs.RunInput();
+    runMsgParams.input.query_version = new interfaceCtrlMsgs.QueryVersion();
+
+    return sendRunMessage(this.receiver, runMsgParams).then(function(
+      runResponseMsgParams) {

[yzshen1, 2017/02/11 01:11:29]

4 spaces.

[wangjimmy, 2017/02/13 20:43:07]

Done.

+      return runResponseMsgParams.output.query_version_result.version;
+    });
+  };
+
+  ControlMessageProxy.prototype.requireVersion = function(version) {
+    var runOrClosePipeMsgParams = new
+      interfaceCtrlMsgs.RunOrClosePipeMessageParams();

[yzshen1, 2017/02/11 01:11:29]

4 spaces.

[wangjimmy, 2017/02/13 20:43:07]

Done.

+    runOrClosePipeMsgParams.input = new interfaceCtrlMsgs.RunOrClosePipeInput();
+    runOrClosePipeMsgParams.input.require_version = new
+      interfaceCtrlMsgs.RequireVersion({'version': version});

[yzshen1, 2017/02/11 01:11:29]

4 spaces.

[wangjimmy, 2017/02/13 20:43:07]

Done.

+    sendRunOrClosePipeMessage(this.receiver, runOrClosePipeMsgParams);
+  };
+
+  var exports = {};
+  exports.ControlMessageProxy = ControlMessageProxy;
+
+  return exports;
+});