[Android History] Add a chrome://flags for the Android native history UI

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 cb45ed01dee43012e187d9177ea406d270b2c3c6..c2957e6373897082284a0b72f7812735c1e0b366 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -93663,6 +93663,7 @@ value.
   <int value="-13918890" label="disable-download-notification"/>
   <int value="-11260186" label="enable-offline-pages-as-saved-pages"/>
   <int value="-5052940" label="enable-simplified-fullscreen"/>
+  <int value="-2953333" label="AndroidHistoryManager:disabled"/>
   <int value="-2371418" label="disable-display-list-2d-canvas"/>
   <int value="0" label="BAD_FLAG_FORMAT">
     Command-line flag doesn't start with two dashes.
@@ -93820,6 +93821,7 @@ value.
   <int value="773919225" label="disable-office-editing-component-extension"/>
   <int value="779086132" label="enable-data-reduction-proxy-alt"/>
   <int value="782167080" label="enable-new-qp-input-view"/>
+  <int value="783270752" label="AndroidHistoryManager:enabled"/>
   <int value="803282885" label="PreferHtmlOverPlugins:disabled"/>
   <int value="805567148"
       label="enable-canvas-2d-dynamic-rendering-mode-switching"/>