Implement Ukm Mojo interface.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 0738496bfc2a5ce97414bf885c594f7055105be4..7fa11d7b449e7559686eada26848eed2386e8a05 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -153,6 +153,7 @@
 #include "components/task_scheduler_util/browser/initialization.h"
 #include "components/task_scheduler_util/common/variations_util.h"
 #include "components/translate/core/common/translate_switches.h"
+#include "components/ukm/ukm_interface.h"
 #include "components/url_formatter/url_fixer.h"
 #include "components/variations/variations_associated_data.h"
 #include "components/version_info/version_info.h"
@@ -3107,6 +3108,9 @@ void ChromeContentBrowserClient::ExposeInterfacesToRenderer(
       base::Bind(&rappor::RapporRecorderImpl::Create,
                  g_browser_process->rappor_service()),
       ui_task_runner);
+  registry->AddInterface(
+      base::Bind(&ukm::UkmInterface::Create, g_browser_process->ukm_recorder()),
+      ui_task_runner);
   if (NetBenchmarking::CheckBenchmarkingEnabled()) {
     Profile* profile =
         Profile::FromBrowserContext(render_process_host->GetBrowserContext());