Add Settings bluetooth page test

chrome/test/data/webui/settings/fake_bluetooth_private.js

+// Copyright 2015 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.
+
+/**
+ * @fileoverview Fake implementations of chrome.bluetoothPrivate for testing.
+ */
+cr.define('settings', function() {
+  /**
+   * Fake of the chrome.bluetooth API.
+   * @param {Bluetooth} bluetoothApi

[dpapad, 2015/12/16 22:07:49]

!Bluetooth

[stevenjb, 2015/12/17 00:13:35]

Done.

+   * @constructor
+   * @implements {BluetoothPrivate}
+   */
+  function FakeBluetoothPrivate(bluetoothApi) {
+    this.bluetoothApi_ = bluetoothApi;

[dpapad, 2015/12/16 22:07:49]

/** @private {!Bluetooth} */

[stevenjb, 2015/12/17 00:13:35]

Done.

+  }
+
+  FakeBluetoothPrivate.prototype = {
+    /**
+     * @param {!chrome.bluetoothPrivate.NewAdapterState} adapterState
+     * @param {function():void=} callback

[dpapad, 2015/12/16 22:07:49]

The convention is that optional parameters are named opt_fooBar, in this case
opt_callback, see
https://google.github.io/styleguide/javascriptguide.xml?showone=Naming#Naming.

[stevenjb, 2015/12/17 00:13:35]

Removed in favor of @override.

+     */
+    setAdapterState: function(state, callback) {
+      this.bluetoothApi_.enabled = state.powered;
+      setTimeout(callback);

[dpapad, 2015/12/16 22:07:49]

The 2nd param to setTimeout is required according to the docs. Not sure why
compiler is not catching this (or most likely this file is not being
type-checked by the compiler). Let's change this to

setTimeout(callback, 0);

Also a comment explaining on why do we do this instead of calling the callback
directly would be useful.

[stevenjb, 2015/12/17 00:13:35]

Hmm, not according to
https://developer.mozilla.org/en-US/docs/Web/API/WindowTimers/setTimeout,

We use this pattern (with no delay argument) pretty often to simulate
asynchronous behavior. I'd like to think that is well enough understood not to
comment that every time we use this pattern.

(We can't currently compile the tests without a lot of effort to get
testing.Test to compile, I tried).

[dpapad, 2015/12/17 01:12:54]

Ah, I see that is fine then. There is a mismatch in documentation, I looked it
up at http://www.w3schools.com/jsref/met_win_settimeout.asp where it says
"required" go figure. Also I can only imagine how hard it would be to compile
test_api.js

+    },
+
+    /**
+     * @param {!chrome.bluetoothPrivate.SetPairingResponseOptions} options
+     * @param {function():void=} callback
+     */
+    setPairingResponse: assertNotReached,
+
+    /**
+     * @param {string} deviceAddress
+     * @param {function():void=} callback
+     */
+    disconnectAll: assertNotReached,
+
+    /**
+     * @param {string} deviceAddress
+     * @param {function():void=} callback
+     */
+    forgetDevice: assertNotReached,
+
+    /**
+     * @param {!chrome.bluetoothPrivate.DiscoveryFilter} discoveryFilter
+     * @param {function():void=} callback
+     */
+    setDiscoveryFilter: assertNotReached,
+
+    /**
+     * @param {string} deviceAddress
+     * @param {function(!chrome.bluetoothPrivate.ConnectResultType):void=}
+     *     callback
+     */
+    connect: assertNotReached,
+
+    /**
+     * @param {string} deviceAddress
+     * @param {function():void=} callback
+     */
+    pair: assertNotReached,
+
+    /** @type {!FakeChromeEvent} */
+    onPairing: new FakeChromeEvent(),

[dpapad, 2015/12/16 22:07:49]

Shouldn't this be placed in the constructor instead? See convention (methods on
prototype, attributes in constructor) at
https://google.github.io/styleguide/javascriptguide.xml?showone=Method_and_pr....

[stevenjb, 2015/12/17 00:13:35]

Let's discuss this here:
https://codereview.chromium.org/1532503003/diff/20001/chrome/test/data/webui/...

While I kind of sorta understand the intent of the guideline, it's pretty
convenient to be able to fake out the entire interface in one place, and this is
a singleton object, used only in tests.

+  };
+
+  return {FakeBluetoothPrivate: FakeBluetoothPrivate};
+});