Add ErrorConsole UI for Extension Install Warnings

chrome/browser/resources/extensions/extension_error.css

+/* Copyright 2013 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. */
+
+.extension-error-list a {
+  cursor: pointer;
+}
+
+.extension-error-list-contents {
+  -webkit-padding-start: 20px;
+  list-style-type: none;
+}
+
+.extension-error-list-show-more {
+  cursor: pointer;
+  text-align: center;
+  width: 100%;
+}
+
+.extension-error-simple-wrapper {
+  display: -webkit-box;
+  width: 100%;
+}
+
+.extension-error-simple-wrapper >:first-child {
+  width: 85%;
+}
+
+.extension-error-icon-error,
+.extension-error-icon-log,
+.extension-error-icon-warn {
+  -webkit-margin-end: 3px;
+  -webkit-margin-start: 3px;
+  height: 15px;
+  vertical-align: middle;
+  width: 15px;
+}
+
+.extension-error-icon-error {
+  content: url('extension_error_error.png');
+}
+
+.extension-error-icon-warn {
+  content: url('extension_error_warn.png');
+}
+
+.extension-error-icon-log {
+  content: url('extension_error_log.png');
+}
+
+.extension-error-message {
+  color: rgba(200, 50, 50, 255);
+}