Moved --top-chrome-md command line switch from chrome_switches to ui_base_switches.

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 f5a2958cf40b5e8f661e4a13bdb73ed486a20969..3b7e7249574f5c8c9ddda5f29707d60cf98ddcf2 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -59052,6 +59052,7 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="-979057409" label="enable-seccomp-filter-sandbox"/>
   <int value="-979034258" label="disable-ntp-other-sessions-menu"/>
   <int value="-972425050" label="gesture-editing"/>
+  <int value="-951394314" label="top-chrome-md"/>
   <int value="-949178861" label="enable-new-avatar-menu"/>
   <int value="-926422468" label="disable-embedded-shared-worker"/>
   <int value="-918618075" label="enable-service-worker"/>
@@ -59277,6 +59278,7 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="1221559505" label="enable-spelling-feedback-field-trial"/>
   <int value="1237297772" label="no-pings"/>
   <int value="1245889469" label="enable-surface-worker"/>
+  <int value="1247293682" label="topchrome-md"/>
   <int value="1250071868" label="disable-timezone-tracking-option"/>
   <int value="1253698118" label="ash-disable-stable-overview-order"/>
   <int value="1257980502" label="disable-accelerated-video-decode"/>