[MD Bookmarks] Refactor window timer mocking.

chrome/test/data/webui/md_bookmarks/test_timer_proxy.js

+// 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.
+
+suiteSetup(function() {
+  cr.define('bookmarks', function() {
+    var TestTimerProxy = function(data) {
+      bookmarks.TimerProxy.call(this);
+
+      this.immediatelyResolveTimeouts = true;
+
+      this.timeoutIds_ = 0;
+
+      /** @private {Object<number, Function>} */

[tsergeant, 2017/06/13 06:48:43]

We can do better than Object:

!Map<number, !Function>

[calamity, 2017/06/16 02:59:26]

Done.

+      this.activeTimeouts_ = new Map();
+    };
+
+    TestTimerProxy.prototype = {
+      __proto__: bookmarks.TimerProxy.prototype,
+
+      /**
+       * @param {Function|string} fn
+       * @param {number=} delay
+       * @return {number}
+       * @override
+       */
+      setTimeout: function(fn, delay) {
+        if (this.immediatelyResolveTimeouts)
+          fn();
+        else
+          this.activeTimeouts_[this.timeoutIds_] = fn;
+
+        return this.timeoutIds_++;

[tsergeant, 2017/06/13 06:48:43]

Optional: You could use cr.createUid() here, since it does basically exactly
what you're already doing.

[calamity, 2017/06/16 02:59:26]

My ids start fighting with other uids which make me unable to test for exact
timeout ids in my test.

[tsergeant, 2017/06/16 03:54:22]

Oh, sure, I forgot that you were hardcoding the values in the tests.

+      },
+
+      /**
+       * @param {number|undefined?} id
+       * @override
+       */
+      clearTimeout: function(id) {
+        this.activeTimeouts_.delete(id);
+      },
+
+      /**
+       * Run the function associated with a timeout id and clear it from the
+       * active timeouts.
+       * @param {number} id
+       */
+      runTimeoutFn: function(id) {
+        this.activeTimeouts_[id]();
+        this.clearTimeout(id);
+      },
+
+      /**
+       * Returns whether a given timeout id has been run or cleared.

[tsergeant, 2017/06/13 06:48:43]

This sentence is a little tough to read. How about

"Returns true if a given timeout id has not been run or cleared"

[calamity, 2017/06/16 02:59:26]

Done.

+       * @param {number} id
+       * @return {boolean}
+       */
+      hasTimeout: function(id) {
+        return this.activeTimeouts_.has(id);
+      },
+    };
+
+    return {
+      TestTimerProxy: TestTimerProxy,
+    };
+  });
+});