Add metrics for PasswordForm submission types

components/autofill/core/common/password_form.h

Index: components/autofill/core/common/password_form.h
diff --git a/components/autofill/core/common/password_form.h b/components/autofill/core/common/password_form.h
index 8bcf44850a8d6f537694bcedfcddb219b24931a7..065d8de4089ce46b642a485fd81c644d85d2ca02 100644
--- a/components/autofill/core/common/password_form.h
+++ b/components/autofill/core/common/password_form.h
@@ -84,6 +84,18 @@ struct PasswordForm {
     LAYOUT_LAST = LAYOUT_LOGIN_AND_SIGNUP
   };
 
+  // Events that Password Manager uses as triggers for checking a success of a

[engedy, 2017/05/10 13:07:43]

Phrasing nit:

// Events observed by the Password Manager that indicate either that a form is
potentially being submitted, or that a form has already been successfully
submitted. Recorded into a UMA histogram, so order of enumerators should not be
changed. 

[dvadym, 2017/05/10 14:09:26]

Thanks, done

+  // password form submission.
+  enum class SubmissionIndicatorEvent {
+    NONE,
+    HTML_FORM_SUBMISSION,
+    INPAGE_NAVIGATION,

[engedy, 2017/05/10 13:07:42]

nit: SAME_DOCUMENT_NAVIGATION for consistency

[dvadym, 2017/05/10 14:09:26]

Done.

+    XHR_SUCCEEDED,
+    FRAME_DETACHED,
+    BY_CONTEXT_MENU_CLICK,

[engedy, 2017/05/10 13:07:43]

nit: This sounds like an implementation detail. Have you considered naming this
MANUAL_SAVE_OVERRIDE?

[dvadym, 2017/05/10 14:09:26]

Done.

+    SUBMISSION_EVENT_COUNT

[engedy, 2017/05/10 13:07:42]

nit: SUBMISSION_INDICATOR_EVENT_COUNT

[dvadym, 2017/05/10 14:09:26]

Done.

+  };
+
   // The "Realm" for the sign-on. This is scheme, host, port for SCHEME_HTML.
   // Dialog based forms also contain the HTTP realm. Android based forms will
   // contain a string of the form "android://<hash of cert>@<package name>"
@@ -278,6 +290,9 @@ struct PasswordForm {
   // If true, this form looks like SignUp form according to local heuristics.
   bool does_look_like_signup_form;
 
+  // Type of event which was used for this form submission.

[engedy, 2017/05/10 13:07:42]

Phrasing nit: 

// The type of the event that was taken as an indication that this form is being
or has already been submitted. This field is not persisted and filled out only
for submitted forms.

[dvadym, 2017/05/10 14:09:26]

Thanks, done

+  SubmissionIndicatorEvent submission_event;
+
   // Return true if we consider this form to be a change password form.
   // We use only client heuristics, so it could include signup forms.
   bool IsPossibleChangePasswordForm() const;
@@ -315,6 +330,9 @@ base::string16 OtherPossibleUsernamesToString(
 std::ostream& operator<<(std::ostream& os, PasswordForm::Layout layout);
 std::ostream& operator<<(std::ostream& os, const PasswordForm& form);
 std::ostream& operator<<(std::ostream& os, PasswordForm* form);
+std::ostream& operator<<(
+    std::ostream& os,
+    PasswordForm::SubmissionIndicatorEvent submission_event);
 
 }  // namespace autofill