Add metrics for user manually added exceptions

chrome/browser/ui/webui/options/content_settings_handler.cc

Index: chrome/browser/ui/webui/options/content_settings_handler.cc
diff --git a/chrome/browser/ui/webui/options/content_settings_handler.cc b/chrome/browser/ui/webui/options/content_settings_handler.cc
index 3f17e4b2b13b8e8181f4dfd575d70115193049a8..03f3da154d1ecd4149bccefbd694fe3a2d3cd1f9 100644
--- a/chrome/browser/ui/webui/options/content_settings_handler.cc
+++ b/chrome/browser/ui/webui/options/content_settings_handler.cc
@@ -14,6 +14,7 @@
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
@@ -1518,6 +1519,11 @@ void ContentSettingsHandler::SetException(const base::ListValue* args) {
                                     std::string(),
                                     setting_type);
     WebSiteSettingsUmaUtil::LogPermissionChange(type, setting_type);
+
+    size_t num_values;
+    int histogram_value = ContentSettingTypeToHistogramValue(type, &num_values);
+    UMA_HISTOGRAM_ENUMERATION("ContentSettings.AddManualException",
+                              histogram_value, num_values);
   }
 }