metrics: Add leak detector controller in Chrome OS metrics system

chrome/test/BUILD.gn

Index: chrome/test/BUILD.gn
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index ea7f8c9cdb0aa6c538a75d4bb618fbb6e2941dfe..01987eb5bcc47da22a0c7d23692b669c7b24a11c 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -9,6 +9,7 @@ import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//chrome/chrome_tests.gni")
 import("//chrome/test/base/js2gtest.gni")
+import("//components/metrics/leak_detector/leak_detector.gni")
 import("//testing/test.gni")
 
 if (is_android) {
@@ -1878,6 +1879,9 @@ test("unit_tests") {
     ]
     sources -= [ "../browser/signin/signin_manager_unittest.cc" ]
   }
+  if (is_chromeos && enable_leak_detector) {
+    sources += [ "../browser/metrics/leak_detector_controller_unittest.cc" ]
+  }
   if (use_x11) {
     deps += [ "//ui/events/devices" ]
     data_deps += [ "//tools/xdisplaycheck" ]