Add "emulate push event" button to ServiceWorkersView in DevTools [2/2 blink]

Source/devtools/front_end/resources/serviceWorkersView.css

 /*
  * Copyright 2015 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.
  */
 
 .service-workers-view {
     overflow: auto;
 }
 
@@ skipping 144 matching lines @@
 }
 
 .service-workers-version-script-url {
     border-left: 1px solid #e1e1e1;
     display: block;
     flex: 3 3 0;
     overflow: hidden;
     text-overflow: ellipsis;
 }
 
-.service-workers-start-button {
-    -webkit-mask-position: -64px -48px;
-}
-
-.service-workers-stop-button {
-    -webkit-mask-position: -96px -48px;
-}
-
-.service-workers-delete-button {
-    -webkit-mask-position: -128px -24px;
-    position: absolute;
-    top: 50%;
-    transform: translate(0, -50%);
-}
-
 .service-workers-button {
     -webkit-mask-image: url(Images/statusbarButtonGlyphs.png);
     -webkit-mask-size: 320px 144px;
     background-color: rgba(0, 0, 0, 0.75);
     height: 24px;
     opacity: 0.8;
     width: 32px;
     border: 0;
     padding: 0;
 }
 
 @media (-webkit-min-device-pixel-ratio: 1.5) {
 .service-workers-button {
     -webkit-mask-image: url(Images/statusbarButtonGlyphs_2x.png);
 }
 } /* media */
 
 .service-workers-button:hover {
     opacity: 1;
 }
 
 .service-workers-button:active {
     opacity: 0.8;
 }
 
+.service-workers-button:disabled {
+    opacity: 0.5;
+}
+
+.service-workers-start-button {
+    -webkit-mask-position: -64px -48px;
+}
+
+.service-workers-stop-button {
+    -webkit-mask-position: -96px -48px;
+}
+
+.service-workers-delete-button {
+    -webkit-mask-position: -128px -24px;
+}
+
+.service-workers-push-button {
+    -webkit-mask-image: url(Images/notifications.svg);
+    -webkit-mask-position: 7px 3px;
+    -webkit-mask-repeat: no-repeat;
+    -webkit-mask-size: 18px 18px;
+}
+
 .service-workers-error {
     display: flex;
 }
 
 .service-workers-error-message {
     font-weight: bold;
 }
 
 .service-workers-info {
     display: flex;
@@ skipping 31 matching lines @@
     background-color: #996600;
 }
 
 .service-workers-color-8 {
     background-color: #9900CC;
 }
 
 .service-workers-color-9 {
     background-color: #336600;
 }