Measure how often HTTPS credentials cannot be filled into HTTP forms.

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 22e2dbc85c346c590054c7191e3e9c858ed8153d..0d847c3ee9423a1f98746b173c4d5ede36b6d9cc 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -50162,6 +50162,28 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="PasswordManager.SuppressedAccount"
+    enum="PasswordManagerSuppressedAccountType">
+  <owner>engedy@chromium.org</owner>
+  <summary>
+    Records, for each password form seen by the password manager, whether there
+    were `suppressed` credentials, meaning stored credentials that were not
+    filled because they had an origin that &quot;almost but not quite&quot;
+    matched the origin of the observed form. If there were such credentials, the
+    histogram also records whether the username and password of such suppressed
+    credentials matched those submitted.
+  </summary>
+</histogram>
+
+<histogram name="PasswordManager.SuppressedAccountsWereChecked" enum="Boolean">

[rkaplow, 2017/05/23 20:13:43]

is this supposed to be QueryingSuppressedAccountsFinished?

[engedy, 2017/05/23 20:40:18]

Hmm, yes. Fixed. How did the PRESUBMIT check not catch this?

+  <owner>engedy@chromium.org</owner>
+  <summary>
+    Records, for each password form seen by the password manager, whether the
+    PasswordStore responded quickly enough so that
+    PasswordManager.SuppressedAccount. histogram samples could be computed.

[rkaplow, 2017/05/23 20:13:43]

extra .

[engedy, 2017/05/23 20:40:18]

Done.

+  </summary>
+</histogram>
+
 <histogram name="PasswordManager.SyncCredentialFiltered"
     enum="CredentialFilteredType">
   <owner>gcasto@chromium.org</owner>
@@ -90477,6 +90499,20 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <affected-histogram name="PasswordManager.SavePasswordPromptResponse"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="PasswordManagerSuppressedAccountReason">

[rkaplow, 2017/05/23 20:13:43]

unclear to me why this is needed if there is only a single prefix. Are you
planning to extend this?

[engedy, 2017/05/23 20:40:18]

Yep, in a follow-up CL, and I wanted to start using the final names for this
histogram already.

Would you rather I just hard-coded this prefix into the histogram name for now?

+  <suffix name="HTTPSNotHTTP"
+      label="The credential was suppressed because it was for an HTTPS origin
+             whereas the observed form was for an HTTP origin."/>
+  <affected-histogram name="PasswordManager.SuppressedAccount"/>
+</histogram_suffixes>
+
+<histogram_suffixes name="PasswordManagerSuppressedAccountType">
+  <suffix name="Generated" label="The password was originally auto-generated."/>
+  <suffix name="Manual"
+      label="The password was originally typed in by the user."/>
+  <affected-histogram name="PasswordManager.SuppressedAccount"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="PasswordProtectionTrigger" separator=".">
   <suffix name="PasswordFieldOnFocus"
       label="Password protection triggered by password field on focus event."/>