Record Autofill form events specially for nonsecure pages

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 186aa8292df8b74a7ed4768bae0df40958c6796d..eb18e2082d7f78acd158325198ab17972ecd6c94 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -3364,7 +3364,7 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
     the data after and then submitted, we would only emit one "Submitted
     with server suggestion filled (once)"; - The submission segmentation
     works by checking what kind of data was last filled for this type of form in
-    the page load. So, if I user initially filled with local data and after that
+    the page load. So, if a user initially filled with local data and after that
     filled with server, we will only emit "Submitted with server suggestion
     filled (once)".
   </details>
@@ -3383,7 +3383,27 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
     the data after and then submitted, we would only emit one &quot;Submitted
     with server suggestion filled (once)&quot;; - The submission segmentation
     works by checking what kind of data was last filled for this type of form in
-    the page load. So, if I user initially filled with local data and after that
+    the page load. So, if a user initially filled with local data and after that
+    filled with server, we will only emit &quot;Submitted with server suggestion
+    filled (once)&quot;.
+  </details>
+</histogram>
+
+<histogram name="Autofill.FormEvents.CreditCard.OnNonsecurePage"
+    enum="AutofillFormEvent">
+  <owner>estark@chromium.org</owner>
+  <summary>
+    Autofill form events for credit card forms on nonsecure pages. These are
+    recorded when the user interacts with a form requesting a credit card.
+  </summary>
+  <details>
+    Important caveat about submission metrics: - Submission using autofill data
+    is determined by simply evaluating if there was a fill operation in this
+    page. So, if the user filled with local data, completed erased or modified
+    the data after and then submitted, we would only emit one &quot;Submitted
+    with server suggestion filled (once)&quot;; - The submission segmentation
+    works by checking what kind of data was last filled for this type of form in
+    the page load. So, if a user initially filled with local data and after that
     filled with server, we will only emit &quot;Submitted with server suggestion
     filled (once)&quot;.
   </details>