cros: Add flag to enable pin on sign-in screen.

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 80c319a3a27d6c3692566ed2f6551d1d33277015..c948d7a00e05ff05a54d2fccdb7d4beb658f285e 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -101187,6 +101187,7 @@ from previous Chrome versions.
   <int value="-1478876902" label="disable-permission-action-reporting"/>
   <int value="-1473668019" label="token-binding:disabled"/>
   <int value="-1473136627" label="enable-web-payments"/>
+  <int value="-1469228683" label="QuickUnlockPinSignin:disabled"/>
   <int value="-1467332609" label="tab-management-experiment-type-anise"/>
   <int value="-1466990325" label="CrosCompUpdates:enabled"/>
   <int value="-1463410070" label="IPH_DemoMode:enabled"/>
@@ -101487,6 +101488,7 @@ from previous Chrome versions.
   <int value="-279493876" label="WebVRExperimentalRendering:enabled"/>
   <int value="-278347667" label="default-tile-height"/>
   <int value="-277144896" label="enable-viewport-meta"/>
+  <int value="-275164173" label="QuickUnlockPinSignin:enabled"/>
   <int value="-268357961" label="enable-feature-policy"/>
   <int value="-254887599" label="google-profile-info"/>
   <int value="-250721831" label="AndroidAutofillAccessibility:disabled"/>