Implement new password separated sign in flow for chrome desktop.

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 60b1d416891cc1b8f68eac8910ac98a2af4b066b..73b5f05a75cb4e05b62d5ef25f72cf02ed59b4c1 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -64386,6 +64386,7 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="630947363" label="touch-events"/>
   <int value="643725031" label="disable-touch-feedback"/>
   <int value="650602639" label="enable-autofill-keyboard-accessory-view"/>
+  <int value="680181055" label="disable-new-gaia-signin-flow"/>
   <int value="683410401"
       label="enable-proximity-auth-bluetooth-low-energy-discovery"/>
   <int value="689489984" label="disable-zero-suggest"/>
@@ -64544,6 +64545,7 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="1821723343" label="disable-saml-signin"/>
   <int value="1844110073" label="enable-app-view"/>
   <int value="1847024354" label="enable-hotword-hardware"/>
+  <int value="1854898455" label="enable-new-gaia-signin-flow"/>
   <int value="1855524566" label="allow-insecure-websocket-from-https-origin"/>
   <int value="1861251313"
       label="enable-message-center-always-scroll-up-upon-notification-removal"/>