Add metrics to measure time elapsed between form load and form submission with or without Autofill.

chrome/browser/autofill/form_structure.h

Index: chrome/browser/autofill/form_structure.h
diff --git a/chrome/browser/autofill/form_structure.h b/chrome/browser/autofill/form_structure.h
index 4f154d450332b72992c9ffc1212270a61dd3c93a..2dea00bda61c408889a6cf84de8d292be18ce654 100644
--- a/chrome/browser/autofill/form_structure.h
+++ b/chrome/browser/autofill/form_structure.h
@@ -30,6 +30,10 @@ enum UploadRequired {
 
 class AutofillMetrics;
 
+namespace base {
+class TimeTicks;
+}
+
 namespace buzz {
 class XmlElement;
 }
@@ -106,8 +110,12 @@ class FormStructure {
 
   // Logs quality metrics for |this|, which should be a user-submitted form.
   // This method should only be called after the possible field types have been
-  // set for each field.
-  void LogQualityMetrics(const AutofillMetrics& metric_logger) const;
+  // set for each field.  |interaction_time| should be a timestamp corresponding
+  // to the user's first interaction with the form.  |submission_time| should be
+  // a timestamp corresponding to the form's submission.
+  void LogQualityMetrics(const AutofillMetrics& metric_logger,
+                         const base::TimeTicks& interaction_time,
+                         const base::TimeTicks& submission_time) const;
 
   const AutofillField* field(size_t index) const;
   AutofillField* field(size_t index);