Experiment to add bank name in autofill 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 d1a99e83386f5c53227ce18ecb729103ccc3b646..f08a9757d125e0a60e9e765b775e3edf29e20df8 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -4118,6 +4118,25 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </details>
 </histogram>
 
+<histogram name="Autofill.FormEvents.CreditCard.BankNameDisplayed"
+    enum="BankNameDisplayedFormEvent">
+  <owner>szhangcs@google.com</owner>
+  <summary>
+    Autofill form events for credit card forms. These are recorded when the user
+    interacts with a form requesting a credit card, a dropdown of suggestions
+    is shown and at least one of the suggestions has a bank name. Form events
+    are logged at most once per page load.
+  </summary>
+  <details>
+    These metrics are used to measure the impact of the bank name experiment. 
+    They are used to calculate the CTR of the autofill UI with bank names
+    available. Not all credit cards will have bank names even if we launch the
+    experiment. With these metrics we can run the experiment on 2 groups. For
+    one group, we will show bank names if available. For the other, we won't
+    shown.
+  </details>
+</histogram>
+
 <histogram name="Autofill.FormEvents.CreditCard.OnNonsecurePage"
     enum="AutofillFormEvent">
   <owner>estark@chromium.org</owner>