Add metrics for new CBD dialog

components/browsing_data/core/clear_browsing_data_tab.h

Index: components/browsing_data/core/clear_browsing_data_tab.h
diff --git a/components/browsing_data/core/clear_browsing_data_tab.h b/components/browsing_data/core/clear_browsing_data_tab.h
index cca479e2a808abd45b63c24d48663ab0b4d1b63e..22efd849bb55831f003f1fa65be9aaad47307bc2 100644
--- a/components/browsing_data/core/clear_browsing_data_tab.h
+++ b/components/browsing_data/core/clear_browsing_data_tab.h
@@ -14,6 +14,8 @@ namespace browsing_data {
 // TODO(dullweber): Maybe rename "ADVANCED" to "DEFAULT" because it is used in
 //   multiple places without a differentiation between advanced and basic.
 //
+// Do not change the values here, as they are used for UMA histograms.
+//
 // A Java counterpart will be generated for this enum.
 // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser.browsing_data
 enum class ClearBrowsingDataTab { BASIC, ADVANCED, NUM_TYPES };