tracing: the agent registry implementation

services/resource_coordinator/BUILD.gn

Index: services/resource_coordinator/BUILD.gn
diff --git a/services/resource_coordinator/BUILD.gn b/services/resource_coordinator/BUILD.gn
index a0b2daf0d6ac801191ad023e640876017e884743..e48a0d63a0f79b4dcf378c53448d9be94a4deaa3 100644
--- a/services/resource_coordinator/BUILD.gn
+++ b/services/resource_coordinator/BUILD.gn
@@ -56,6 +56,7 @@ source_set("tests") {
     "memory/coordinator/process_map_unittest.cc",
     "public/cpp/memory/process_local_dump_manager_impl_unittest.cc",
     "public/cpp/tracing/chrome_trace_event_agent_unittest.cc",
+    "tracing/agent_registry_unittest.cc",
   ]
 
   deps = [
@@ -64,6 +65,7 @@ source_set("tests") {
     "//base/test:test_support",
     "//mojo/public/cpp/bindings",
     "//services/resource_coordinator/public/cpp:resource_coordinator_cpp",
+    "//services/resource_coordinator/tracing:lib",
     "//testing/gtest",
   ]