[MD Extensions] Move search field out of downloads, use it in extensions

ui/webui/resources/js/cr/ui/search_field.js

Index: ui/webui/resources/js/cr/ui/search_field.js
diff --git a/ui/webui/resources/js/cr/ui/search_field.js b/ui/webui/resources/js/cr/ui/search_field.js
new file mode 100644
index 0000000000000000000000000000000000000000..646080b2df04c4483e34684b9e256addcf9029fe
--- /dev/null
+++ b/ui/webui/resources/js/cr/ui/search_field.js
@@ -0,0 +1,61 @@
+// 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.
+
+cr.define('cr.ui', function() {
+  var SearchField = Polymer({
+    is: 'search-field',
+
+    properties: {
+      showingSearch_: {
+        type: Boolean,
+        value: false,
+      },
+    },
+
+    setDelegate: function(delegate) {
+      this.delegate_ = delegate;
+    },
+
+    getValue: function() {
+      return this.$['search-input'].value;
+    },
+
+    /** @private */
+    onSearchTermSearch_: function() {
+      if (this.delegate_)
+        this.delegate_.onSearchTermSearch(this.$['search-input'].value);
+    },
+
+    /** @private */
+    onSearchTermKeydown_: function(e) {
+      assert(this.showingSearch_);
+      if (e.keyIdentifier == 'U+001B')  // Escape.
+        this.toggleShowingSearch_();
+    },
+
+    /** @private */
+    toggleShowingSearch_: function() {
+      this.showingSearch_ = !this.showingSearch_;
+
+      if (this.showingSearch_) {
+        this.$['search-input'].focus();
+      } else {
+        this.$['search-input'].value = '';
+        this.onSearchTermSearch_();
+      }
+    },
+  });
+
+  /** @interface */
+  SearchField.Delegate = function() {};
+
+  SearchField.Delegate.prototype = {
+    /**
+     * @param {string} value
+     */
+    onSearchTermSearch: assertNotReached,
+  };
+
+  return {SearchField: SearchField};
+});