DevTools: Audits2 use built-in dialog overlay

BUG=845406,847350,846607

Change-Id: Id3ed220dcaf00cfbed5ba7b02e27412eab09b219
Reviewed-on: https://chromium-review.googlesource.com/1076325
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Paul Irish <paulirish@chromium.org>
Commit-Queue: Paul Irish <paulirish@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#562528}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 3fce93a6536e0fd46e21ffb5f3635f1e544696ef
diff --git a/front_end/audits2/Audits2StatusView.js b/front_end/audits2/Audits2StatusView.js
index 98cfc67..3198f95 100644
--- a/front_end/audits2/Audits2StatusView.js
+++ b/front_end/audits2/Audits2StatusView.js
@@ -23,6 +23,8 @@
     this._scheduledFastFactTimeout = null;
 
     this._dialog = new UI.Dialog();
+    this._dialog.setDimmed(true);
+    this._dialog.setCloseOnEscape(false);
     this._dialog.setOutsideClickCallback(event => event.consume(true));
     this._render();
   }