HTTP Bad: Split out UMA metrics for password vs credit card "Not secure" warnings

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 0b8814dcb5fa9038c933c872745555b49bd0dd77..d62e1bed091c794ca489ea8ec249c6e80feaabb5 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -56579,14 +56579,25 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
-<histogram name="Security.HTTPBad.UserWarnedAboutSensitiveInput"
+<histogram name="Security.HTTPBad.UserWarnedAboutSensitiveInput.CreditCard"

[estark, 2016/11/09 15:56:46]

isherman will tell you for sure, but I think the right way to remove the old one
is to leave it here and add an <obsolete> tag to it that explains why it's no
longer used. (Search for 'obsolete' in this file to see an example.)

[lshang, 2016/11/10 04:53:55]

Done.

     enum="BooleanShown">
   <owner>elawrence@chromium.org</owner>
   <owner>estark@chromium.org</owner>
   <summary>
     Whether a &quot;Not Secure&quot; warning was shown in the omnibox because a
-    security-sensitive form field was rendered in a non-secure context. Logged
-    at most once per main-frame navigation.
+    credit card form field was rendered in a non-secure context. Logged at most
+    once per main-frame navigation.
+  </summary>
+</histogram>
+
+<histogram name="Security.HTTPBad.UserWarnedAboutSensitiveInput.Password"
+    enum="BooleanShown">
+  <owner>elawrence@chromium.org</owner>
+  <owner>estark@chromium.org</owner>
+  <summary>
+    Whether a &quot;Not Secure&quot; warning was shown in the omnibox because a
+    password form field was rendered in a non-secure context. Logged at most
+    once per main-frame navigation.
   </summary>
 </histogram>