DevTools: Switch network panel back to frame-based filmstrip.

Source/devtools/front_end/components_lazy/filmStripView.css

 /*
  * Copyright (c) 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.
  */
 
 .film-strip-view {
     overflow-x: auto;
     overflow-y: hidden;
     align-content: flex-start;
     min-height: 60px;
 }
 
 .film-strip-view .label {
     margin: auto;
     font-size: 18px;
     color: #999;
 }
 
 .film-strip-view .frame {
     display: flex;
     flex-direction: column;
     align-items: center;
-    padding: 5px 0;
+    padding: 4px 0;
     flex: none;
 }
 
 .film-strip-view .frame-limit-reached {
     font-size: 24px;
     color: #888;
     justify-content: center;
     display: inline-flex;
     flex-direction: column;
     flex: none;
@@ skipping 11 matching lines @@
     pointer-events: none;
 }
 
 .film-strip-view .frame .thumbnail img {
     height: auto;
     width: auto;
     max-width: 80px;
     max-height: 50px;
     pointer-events: none;
     border-right: solid 1px #eee;
+    flex: 0 0 auto;
 }
 
 .film-strip-view .frame .time {
     font-size: 10px;
-    margin-top: 4px;
+    margin-top: 2px;
 }