[Autofill] Add FormEvent logging for "will submit form".

components/autofill/core/browser/autofill_metrics.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/autofill/core/browser/autofill_metrics.h"
 
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/time/time.h"
@@ skipping 547 matching lines @@
   if (!has_logged_suggestion_filled_) {
     has_logged_suggestion_filled_ = true;
     logged_suggestion_filled_was_server_data_ =
         profile.record_type() == AutofillProfile::SERVER_PROFILE;
     Log(profile.record_type() == AutofillProfile::SERVER_PROFILE
         ? AutofillMetrics::FORM_EVENT_SERVER_SUGGESTION_FILLED_ONCE
         : AutofillMetrics::FORM_EVENT_LOCAL_SUGGESTION_FILLED_ONCE);
   }
 }
 
+void AutofillMetrics::FormEventLogger::OnWillSubmitForm() {
+  // Not logging this kind of form if we haven't logged a user interaction.
+  if (!has_logged_interacted_)
+    return;
+
+  Log(AutofillMetrics::FORM_EVENT_WILL_SUBMIT);

[Ilya Sherman, 2015/03/18 22:42:10]

Should this event be logged only once, as below?

[Mathieu, 2015/03/23 15:24:02]

+walter

I wanted to capture all OnWillSubmit events (possibly AJAX submissions) before
the page navigated. I'm not sure why there is logic to avoid logging
OnFormSubmitted twice. Perhaps walter can advise?

[Walter Cacau, 2015/03/23 19:06:37]

The idea was that we were tracking the basic user flow from:

INTERACT -> SHOW SUGGESTION -> SELECT/FILL SUGGESTION -> SUBMIT
For that, we wanted it to be counted only once per page load.

What is the indent in capturing the FORM_EVENT_WILL_SUBMIT? It may make sense to
create also a FORM_EVENT_WILL_SUBMIT_[CASE]_ONCE if we think there are quite a
few forms that simply submit with ajax without us being able to detect the user
click.

+}
+
 void AutofillMetrics::FormEventLogger::OnDidSubmitForm() {
   // Not logging this kind of form if we haven't logged a user interaction.
   if (!has_logged_interacted_)
     return;
 
   // Not logging twice.
   if (has_logged_submitted_)
     return;
   has_logged_submitted_ = true;
 
@@ skipping 26 matching lines @@
   else if (is_server_data_available_ && !is_local_data_available_)
     name += ".WithOnlyServerData";
   else if (!is_server_data_available_ && is_local_data_available_)
     name += ".WithOnlyLocalData";
   else
     name += ".WithBothServerAndLocalData";
   LogUMAHistogramEnumeration(name, event, NUM_FORM_EVENTS);
 }
 
 }  // namespace autofill