Adding the first set of remote test cases and associated framework.

remoting/tools/remote_test_helper/jsonrpc.js

Index: remoting/tools/remote_test_helper/jsonrpc.js
diff --git a/remoting/tools/remote_test_helper/jsonrpc.js b/remoting/tools/remote_test_helper/jsonrpc.js
new file mode 100644
index 0000000000000000000000000000000000000000..08b77b18f9cfa70ba7665c82ec396716bad4861e
--- /dev/null
+++ b/remoting/tools/remote_test_helper/jsonrpc.js
@@ -0,0 +1,62 @@
+// Copyright (c) 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.
+
+var jsonRpc = {};
+jsonRpc.responseObject = null;
+
+jsonRpc.setLastEvent = function(action, value, modifiers) {
+  var request = jsonRpc.generateJsonRpcRequest(
+    'SetLastEvent', [action, value, modifiers]);
+  return jsonRpc.sendRpcRequest(request);
+}
+
+jsonRpc.getLastEvent = function() {
+  var request = jsonRpc.generateJsonRpcRequest('GetLastEvent', []);
+  return jsonRpc.sendRpcRequest(request);
+}
+
+jsonRpc.clearLastEvent = function() {
+  var request = jsonRpc.generateJsonRpcRequest('ClearLastEvent', []);
+  return jsonRpc.sendRpcRequest(request);
+}
+
+/**
+ * Generate the JSON request.
+ * @param {string} methodname The name of the remote method.
+ * @param {list} params The method parameters to pass.
+ * @param {integer} ident The request id.

[Jamie, 2015/01/08 20:34:37]

{integer} is not a valid type annotation. I think you mean {number}.

I don't know if there's any value in running jscompile over this, but now that
jscompile is integrated into the Chromium build process, it shouldn't be too
difficult. Since this is library code (and therefore not expected to be
exercised in full by any given test), I think it would be worthwhile. It can be
a follow-up CL though.

[Mike Meade, 2015/01/12 18:04:26]

I fixed this to be {number=} and assigned a default value of 0. I also changed
the name to opt_ident.

+ * @return The JSON-RPC request object
+ **/
+jsonRpc.generateJsonRpcRequest = function(methodname, params, ident) {
+  ident = ident == undefined ? '...' : ident;

[Jamie, 2015/01/06 19:31:39]

Why is this needed? Under what circumstances will a zero ident be provided?

[Mike Meade, 2015/01/08 18:58:42]

I wrote this to be a general library module for any test/code to use. I used
'...' as the default parameter for ident, but that shouldn't force other code to
use this as well. Instead of needing to modify this method in later code I just
added the default argument pattern here for the identifier arg.

[Jamie, 2015/01/08 20:34:37]

I think the problem I have with it is that you've declared |ident| as being a
number, but are assigning a string default value to it. That's not prohibited by
JS, but I think it leads to confusing code. I don't see any problem in requiring
an id to be supplied, even for generic library code, but if you do want to keep
it optional, you should do the following:

* Make it explicit by calling it opt_ident and making its type {number=}
* Use === instead of == for comparing it to undefined (== does type conversion
so that, for example "null==undefined" will evaluate to true).
* Consider using 0 (or -1) as a default, instead of '...'

[Mike Meade, 2015/01/12 18:04:26]

Done.

+  var request = {
+    "jsonrpc": "2.0",
+    "method": methodname,
+    "params": params,
+    "id": ident
+    };
+  return request;
+}
+
+/**
+ * Method to POST the request to the RPC server.
+ * @param {object} json_request The JSON request object.
+ **/
+jsonRpc.sendRpcRequest = function(json_request) {

[Jamie, 2015/01/06 19:31:39]

I think it would be better to clear the responseObject here, rather than doing
it from C++.

[Mike Meade, 2015/01/08 18:58:42]

Done.

+  var xhr = new XMLHttpRequest();
+  xhr.open('POST', '/RPC2', true);
+  xhr.onreadystatechange = function () {
+    if (xhr.readyState == 4 && xhr.status == 200) {
+      try {
+        var response = xhr.responseText;
+        jsonRpc.responseObject = JSON.parse(response).response;
+      } catch (err) {
+        console.error('Could not parse server response.');
+        return;
+      }
+    }
+  }
+  string_request = JSON.stringify(json_request);
+  xhr.send(string_request);
+}