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 04bc2a1086f2bc0ac94ba7b8dc45514c25d7d297..673b28d797e084c36a5d90a3068a777496850a91 100644
--- a/chrome/browser/ui/webui/options/content_settings_handler.cc
+++ b/chrome/browser/ui/webui/options/content_settings_handler.cc
@@ -16,6 +16,7 @@
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.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"
@@ -1532,6 +1533,11 @@ void ContentSettingsHandler::SetException(const base::ListValue* args) {
         ContentSettingsPattern::FromString(pattern),
         ContentSettingsPattern::Wildcard(), type, 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);

[raymes, 2016/04/12 23:22:39]

Do you think this histogram will be useful?

[lshang, 2016/04/14 04:55:29]

Done.

   }
 }