Hosting the discardable memory service in the mus process

content/public/app/mojo/content_renderer_manifest.json

 {
   "name": "content_renderer",
   "display_name": "Content (renderer process)",
   "interface_provider_specs": {
     "service_manager:connector": {
       "provides": {
         "browser": [
           "content::mojom::EmbeddedWorkerInstanceClient",
           "content::mojom::EmbeddedWorkerSetup",
           "content::mojom::FrameFactory",
           "content::mojom::RenderWidgetWindowTreeClientFactory",
           "IPC::mojom::ChannelBootstrap",
           "visitedlink::mojom::VisitedLinkNotificationSink",
           "web_cache::mojom::WebCache"
         ],
         "service_manager:service_factory": [
           "service_manager::mojom::ServiceFactory"
         ]
       },
       "requires": {
         "content_browser": [ "renderer" ],
-        "ui": [ "gpu_client" ]
+        "ui": [
+          "discardable_memory",
+          "gpu_client"
+        ]
       }
     },
     "navigation:frame": {
       "provides": {
         "browser": [
           "blink::mojom::AppBannerController",
           "content::mojom::ImageDownloader",
           "mojom::MediaDevicesListener"
         ]
       },
       "requires": {
         "content_browser": [ "renderer" ]
       }
     }
   }
 }