[Signin Error Dialog] (3/3) Added the triggering code

chrome/browser/resources/signin_error/signin_error.css

Index: chrome/browser/resources/signin_error/signin_error.css
diff --git a/chrome/browser/resources/signin_error/signin_error.css b/chrome/browser/resources/signin_error/signin_error.css
new file mode 100644
index 0000000000000000000000000000000000000000..6adf7b754f156fe7dbf0dd6c81cb93fd374f9d5d
--- /dev/null
+++ b/chrome/browser/resources/signin_error/signin_error.css
@@ -0,0 +1,49 @@
+/* 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. */
+
+body {
+  margin: 0;
+  padding: 0;
+}
+
+.container {
+  background-color: white;
+  color: #333;
+  overflow: hidden;
+  width: 448px;
+}
+
+.top-title-bar {
+  align-items: center;
+  border-bottom: 1px solid lightgray;

[tommycli, 2016/08/23 19:15:38]

Are we sure we want to just use 'lightgray' instead of a polymer color?

[Jane, 2016/08/24 13:40:31]

Replaced with paper-grey-300. I was just copying the style from
sync-confirmation, but paper-grey-300 should be good.

+  display: flex;
+  font-size: 16px;
+  height: 52px;
+  padding: 0 24px;
+}
+
+.details {
+  margin-bottom: 8px;
+  margin-top: 16px;
+  padding: 0 24px;
+}
+
+.action-container {
+  display: flex;
+  justify-content: flex-end;
+  padding: 16px;
+}
+
+#switchButton,
+#secondaryConfirmButton,
+#primaryConfirmButton {
+  line-height: 16px;
+  margin: 0;
+  padding: 8px 16px;
+}
+
+#switchButton {
+  -webkit-margin-start: 8px;
+}
+