Convert FieldTrialActivated to use mojo.

chrome/common/BUILD.gn

Index: chrome/common/BUILD.gn
diff --git a/chrome/common/BUILD.gn b/chrome/common/BUILD.gn
index c2310d32ab24d68b5db3c6821555ff89d8c2b8e6..b7cef710a75131a543b4a66960de2e01bae0a10c 100644
--- a/chrome/common/BUILD.gn
+++ b/chrome/common/BUILD.gn
@@ -165,6 +165,7 @@ static_library("common") {
   public_deps = [
     ":features",
     ":mojo_bindings",
+    ":mojo_bindings_no_new_wrapper_types",
     "//base:base",
     "//base:base_static",
     "//base:i18n",
@@ -665,6 +666,12 @@ source_set("app_mode_app_support") {
 
 mojom("mojo_bindings") {
   sources = [
+    "field_trial_recorder.mojom",
+  ]
+}
+
+mojom("mojo_bindings_no_new_wrapper_types") {
+  sources = [
     "image_decoder.mojom",
     "network_diagnostics.mojom",
     "resource_usage_reporter.mojom",
@@ -676,5 +683,7 @@ mojom("mojo_bindings") {
     "//url/mojo:url_mojom_gurl",
   ]
 
+  # TODO(nigeltao): eliminate this and merge
+  # :mojo_bindings_no_new_wrapper_types with :mojo_bindings.
   use_new_wrapper_types = false
 }