Added uma for pin unlock set up.

chrome/browser/ui/webui/settings/md_settings_ui.cc

Index: chrome/browser/ui/webui/settings/md_settings_ui.cc
diff --git a/chrome/browser/ui/webui/settings/md_settings_ui.cc b/chrome/browser/ui/webui/settings/md_settings_ui.cc
index e8764b2b0ae1b9acdda6a4377224287e7da7c8e9..90864fa3fef6f542b0411b2a35f28eae8c0e03d3 100644
--- a/chrome/browser/ui/webui/settings/md_settings_ui.cc
+++ b/chrome/browser/ui/webui/settings/md_settings_ui.cc
@@ -10,6 +10,7 @@
 
 #include "base/metrics/histogram_macros.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/webui/metrics_handler.h"
 #include "chrome/browser/ui/webui/settings/about_handler.h"
 #include "chrome/browser/ui/webui/settings/appearance_handler.h"
 #include "chrome/browser/ui/webui/settings/browser_lifetime_handler.h"
@@ -140,6 +141,9 @@ MdSettingsUI::MdSettingsUI(content::WebUI* web_ui, const GURL& url)
   AddSettingsPageUIHandler(AboutHandler::Create(html_source, profile));
   AddSettingsPageUIHandler(ResetSettingsHandler::Create(html_source, profile));
 
+  // Add the metrics handler to write uma stats.
+  web_ui->AddMessageHandler(new MetricsHandler());
+
   // Add all settings resources.
   for (size_t i = 0; i < kSettingsResourcesSize; ++i) {
     html_source->AddResourcePath(kSettingsResources[i].name,