DevTools: Add shadow-editor swatch/icon before box-shadows and text-shadows

third_party/WebKit/Source/devtools/front_end/ui/shadowSwatch.css

+/*
+ * 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.
+ */
+
+:host {
+    white-space: nowrap;
+}
+
+.shadow-swatch {
+    position: relative;
+    margin-left: 1px;
+    margin-right: 2px;
+    width: 10px;
+    height: 10px;
+    top: 1px;
+    display: inline-block;
+    -webkit-user-select: none;
+    line-height: 10px;
+    -webkit-mask-image: url(Images/swatches.png);
+    -webkit-mask-size: 190px 10px;
+    -webkit-mask-position: -20px;
+    background-color: #9C27B0;
+}
+
+@media (-webkit-min-device-pixel-ratio: 1.5) {
+.shadow-swatch {
+    -webkit-mask-image: url(Images/swatches_2x.png);
+}
+} /* media */
+
+.shadow-swatch:hover {
+    background-color: #800080;
+}