DevTools: [Documentation] Add signature section for renderer

Source/devtools/front_end/documentationView.css

 /*
  * Copyright 2014 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.
  */
 
 .documentation-example-code {
     border: 1px dotted black;
     border-radius: 6px;
     padding: 10px;
     margin-bottom: 10px;
 }
 
 .documentation-code {
     border: 1px dotted black;
     border-radius: 6px;
     padding: 10px;
     margin-bottom: 10px;
 }
 
 .documentation-section-title {
     font-size: 120%;
     padding-bottom: 4px;
     font-weight: bold;
 }
 
 .documentation-link {
-    margin-left: 0.5em;
+    margin-left: 5px;
 }
 
 .documentation-highlighted-text {
     font-weight: bold;
 }
 
-.documentation-parameter {
-    margin-left: 5px;
+.documentation-method-signature {
+    font-size: 120% !important;
+    border: 1px solid gray;
+    border-radius: 6px;
+    padding: 10px;
 }
 
 .documentation-section {
     margin-bottom: 15px;
 }
 
+.documentation-section-content {
+    margin-left: 16px;
+}
+
 .documentation-code-tag {
     font-weight: bold;
 }
 
 .documentation-parameter-optional {
     padding: 6px;
     background-color: rgb(219, 234, 249);
+    padding-left: 10px;
+    padding-right: 10px;
     text-decoration: none;
     margin-left: 10px;
     margin-top: -5px;
     border-radius: 5px;
 }
 
 .documentation-parameter-data-type-value {
     margin-right: 5px;
     padding: 6px;
     background-color: rgb(254, 254, 202);
+    padding-left: 10px;
+    padding-right: 10px;
+    border-radius: 5px;
     text-decoration: none;
-    margin-left: 10px;
-    margin-top: 5px;
+}
+
+.documentation-parameter-margin {
+    margin-left: 1ex;
+    margin-top: -0.5ex;
     border-radius: 5px;
 }
 
 .documentation-parameter-name {
     font-size: 120%;
     font-style: italic;
 }
 
 .documentation-page-title {
     font-size: 160%;
     font-weight: bold;
     padding-bottom: 7px;
 }
 
 .documentation-view {
     -webkit-user-select: text;
     padding: 10px;
 }
 
 .documentation-example-description-section {
     margin-bottom: 10px;
 }
 
 .documentation-example-link {
     float: right;
     padding: 6px;
-    background-color: rgb(241, 246, 251);
+    background-color: rgb(219, 234, 249);
+    padding-left: 10px;
+    padding-right: 10px;
     text-decoration: none;
     margin-left: 10px;
     margin-top: 5px;
     border-radius: 5px;
 }
+
+.documentation-example-link:visited {
+    color: rgb(109, 114, 255);
+}
+
+.documentation-text {
+    line-height: 1.5;
+}