[MD Bookmarks] Add skeleton for Material Design Bookmarks

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 4a197ad0bd5b2a7afa30e2f57993d3aa8ffdc9d9..c8fa11d2289249b0428abc11f05a01e672e446c9 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -89884,6 +89884,7 @@ value.
   <int value="-1491417046" label="enable-fullscreen-toolbar-reveal"/>
   <int value="-1490298774" label="enable-captive-portal-bypass-proxy-option"/>
   <int value="-1482685863" label="enable-request-tablet-site"/>
+  <int value="-1480926949" label="MaterialDesignBookmarks:enabled"/>
   <int value="-1478876902" label="disable-permission-action-reporting"/>
   <int value="-1473668019" label="token-binding:disabled"/>
   <int value="-1473136627" label="enable-web-payments"/>
@@ -90362,6 +90363,7 @@ value.
   <int value="983311394" label="tab-management-experiment-type"/>
   <int value="1000706989" label="AutomaticTabDiscarding:disabled"/>
   <int value="1002585107" label="emphasize-titles-in-omnibox-dropdown"/>
+  <int value="1003002105" label="MaterialDesignBookmarks:disabled"/>
   <int value="1007444341" label="enable-prefixed-encrypted-media"/>
   <int value="1015895665" label="drop-sync-credential:enabled"/>
   <int value="1019857902"