Migrate <cr-dialog> from PaperDialogBehavior to native <dialog>.

ui/webui/resources/cr_elements/cr_dialog/cr_dialog.js

Index: ui/webui/resources/cr_elements/cr_dialog/cr_dialog.js
diff --git a/ui/webui/resources/cr_elements/cr_dialog/cr_dialog.js b/ui/webui/resources/cr_elements/cr_dialog/cr_dialog.js
index 9c9d73fdb7eeaf95bb10574131a0d56d354a5b8b..058e914c0ddb16d556c001f74523cc9f44db3379 100644
--- a/ui/webui/resources/cr_elements/cr_dialog/cr_dialog.js
+++ b/ui/webui/resources/cr_elements/cr_dialog/cr_dialog.js
@@ -3,43 +3,30 @@
 // found in the LICENSE file.
 
 /**
- * @fileoverview 'cr-dialog' is a component for showing a modal dialog.
+ * @fileoverview 'cr-dialog' is a component for showing a modal dialog. If the
+ * dialog is closed via close(), a 'close' event is fired. If the dialog is
+ * canceled via cancel(), a 'cancel' event is fired followed by a 'close' event.
+ * Additionally clients can inspect the dialog's |returnValue| property inisde

[Dan Beam, 2016/07/26 23:36:12]

inisde -> inside

[dpapad, 2016/07/27 01:21:47]

Done.

+ * the 'close' callback to determine whether it was canceled or just closed,
+ * where a truthy value means it was not canceled, and a falsy value means it

[Dan Beam, 2016/07/26 23:36:12]

where a truthy value means success, and a falsy value means it was canceled.

[dpapad, 2016/07/27 01:21:47]

Done.

+ * was canceled.
  */
 Polymer({
   is: 'cr-dialog',
+  extends: 'dialog',
 
-  properties: {
-    /** @override */
-    noCancelOnOutsideClick: {
-      type: Boolean,
-      value: true,
-    },
-
-    /** @override */
-    noCancelOnEscKey: {
-      type: Boolean,
-      value: false,
-    },
-
-    /**
-     * @type {!Element}
-     * @override
-     */
-    sizingTarget: {
-      type: Element,
-      value: function() {
-        return assert(this.$$('.body-container'));
-      },
-    },
-
-    /** @override */
-    withBackdrop: {
-      type: Boolean,
-      value: true,
-    },
+  cancel: function() {
+    this.fire('cancel');
+    HTMLDialogElement.prototype.close.call(this);
   },
 
-  behaviors: [Polymer.PaperDialogBehavior],
+  /**
+   * @param {string=} opt_returnValue
+   * @override
+   */
+  close: function(opt_returnValue) {
+    HTMLDialogElement.prototype.close.call(this, 'success');
+  },
 
   /** @return {!PaperIconButtonElement} */
   getCloseButton: function() {