WebUI: Add password manager search feature. Also add tooltips for the URLs.

chrome/browser/resources/options/password_manager.css

+/*
+ * Copyright (c) 2011 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.
+ */
+
+#password-search-column {
+  bottom: 10px;
+  position: absolute;
+  right: 0;
+}
+
+html[dir=rtl] #password-search-column {
+  left: 0;
+  right: auto;
+}
+
+#password-list-headers {
+  position: relative;
+  width: 100%;
+}
+
+#password-list-headers h3 {
+  font-size: 105%;
+  font-weight: bold;
+  margin: 10px 0;
+}
+
+#passwords-title {
+  display: inline-block;
+}