Add Polymer tests for cr-settings-prefs

chrome/test/data/webui/polymer_browser_test_base.js

Index: chrome/test/data/webui/polymer_browser_test_base.js
diff --git a/chrome/test/data/webui/polymer_browser_test_base.js b/chrome/test/data/webui/polymer_browser_test_base.js
index b768ef76f555a034a033641b08b6ae2c3845b7de..94ad963285a64ecd74f87f44d86b6fb3ccbc2ae5 100644
--- a/chrome/test/data/webui/polymer_browser_test_base.js
+++ b/chrome/test/data/webui/polymer_browser_test_base.js
@@ -95,3 +95,25 @@ PolymerTest.getLibraries = function(basePath) {
     return basePath + library;
   });
 };
+
+/**
+ * Returns a promise which asynchronously calls |fn| and is also resolved
+ * asynchronously. Repeated calls to this function ensure each call waits for
+ * the previous promise to resolve, allowing any setTimeouts called by the prior
+ * function to be queued beforehand. For example:
+ *     PolymerTest.async(fn1); PolymerTest.async(fn2).then(success, failure);
+ * If fn1 calls setTimeout(asyncFn), fn2 won't be called until after asyncFn is
+ * called.
+ */
+PolymerTest.async = function(fn) {
+  PolymerTest.lastPromise_ = PolymerTest.lastPromise_.then(function() {
+    return new Promise(function(resolve) {
+      setTimeout(fn);
+      setTimeout(resolve);
+    });
+  });
+  return PolymerTest.lastPromise_;
+};
+
+/** @type {Promise} */

[Dan Beam, 2015/09/14 23:31:48]

nit: @type -> @private

[michaelpg, 2015/09/15 01:17:57]

Done.

+PolymerTest.lastPromise_ = Promise.resolve();