WIP: The tracing service prototype

content/public/app/mojo/content_gpu_manifest.json

 {
   "name": "content_gpu",
   "display_name": "Content (GPU process)",
   "interface_provider_specs": {
     "service_manager:connector": {
       "provides": {
         "browser": [
           "content::mojom::Child",
           "IPC::mojom::ChannelBootstrap",
           "service_manager::mojom::ServiceFactory",
           "ui::mojom::GpuMain"
         ],
         "service_manager:service_factory": [
           "service_manager::mojom::ServiceFactory"
         ]
       },
       "requires": {
+        "*": [ "app" ],
         "content_browser": [ "gpu" ],
         "device": [ "device:power_monitor" ]
       }
     }
   }
 }