DevTools: zoom frames upon double click, iterate over frames using arrows.

Source/devtools/front_end/network/networkPanel.css

Index: Source/devtools/front_end/network/networkPanel.css
diff --git a/Source/devtools/front_end/network/networkPanel.css b/Source/devtools/front_end/network/networkPanel.css
index 66f4f1476e6ce0a9c7c7464368d47b321818b7b1..881e2e41f3b787ff14cd7cc7e84bd72c447ed34f 100644
--- a/Source/devtools/front_end/network/networkPanel.css
+++ b/Source/devtools/front_end/network/networkPanel.css
@@ -256,3 +256,21 @@
     height: 100%;
     position: absolute;
 }
+
+.network-filmstrip-preview {
+    margin: 12px;
+}
+
+.network-filmstrip-preview > img {
+    border: 1px solid #ddd;
+}
+
+.network-filmstrip-preview-footer {
+    display: flex;
+    align-items: center;
+    margin-top: 10px;
+}
+
+.network-filmstrip-preview-label {
+    margin: 8px 2px;
+}