Show client placeholders for Server LoFi images.

third_party/WebKit/Source/platform/RuntimeEnabledFeatures.json5

 {
   // http://dev.chromium.org/blink/runtime-enabled-features
   //
   // This list is used to generate RuntimeEnabledFeatures.h/cpp which contains
   // a class that stores static enablers for all experimental features.
 
   parameters: {
     // Each feature can be assigned a "status":
     // * status=stable: Enable this in all Blink configurations. We are
     //   committed to these APIs indefinitely.
@@ skipping 138 matching lines @@
     },
     {
       name: "ClickRetargetting",
       status: "experimental",
     },
     {
       name: "ClientHints",
       status: "stable",
     },
     {
+      name: "ClientPlaceholdersForServerLoFi",
+    },
+    {
       name: "CoalescedEvents",
       status: "stable",
     },
     {
       name: "ColorCanvasExtensions",
     },
     {
       name: "ColorCorrectRendering",
       status: "experimental",
     },
@@ skipping 975 matching lines @@
     {
       name: "Worklet",
       status: "experimental",
     },
     {
       name: "XSLT",
       status: "stable",
     },
   ],
 }