MD WebUI: Add shared cr-toolbar element

ui/webui/resources/cr_elements/cr_toolbar/cr_toolbar.js

+// Copyright 2016 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.
+
+Polymer({
+  is: 'cr-toolbar',
+
+  behaviors: [CrSearchFieldBehavior],
+
+  properties: {
+    // Name to display in the toolbar, in titlecase.
+    pageName: String,
+    // Prompt text to display in the search field.
+    searchPrompt: String,
+    // Tooltip to display on the clear search button.
+    clearLabel: String,
+  },
+
+  onInputBlur_: function(e) {
+    if (!this.hasSearchText_)
+      this.showingSearch_ = false;
+  },
+
+  showSearch_: function(e) {
+    if (e.target != this.$['clear-search'])

[dpapad, 2016/05/18 23:39:13]

Nit (optional): Change id to clearSearch, such that it can be used without
quotes, this.$.clearSearch

[tsergeant, 2016/05/19 07:11:55]

I was sticking with the style used in cr-search-field, but now seems like a good
time to convert it over. I've converted all the IDs in this element, as well as
in cr-search-field so that the behavior can be consistent between the two.

+      this.showingSearch_ = true;
+  },
+
+  computeLowerPageName_: function(name) {

[dpapad, 2016/05/18 23:39:14]

Type annotations for parameter and return value missing.

[tsergeant, 2016/05/19 07:11:55]

oops, that function is dead code. So, uh

Done.

+    return name.toLowerCase();
+  }
+});