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

chrome/browser/autofill/autofill_manager.h

Index: chrome/browser/autofill/autofill_manager.h
diff --git a/chrome/browser/autofill/autofill_manager.h b/chrome/browser/autofill/autofill_manager.h
index d488a30acb6d0523fae1b1506e689763cb74908c..6bb416acc6728732861211c4cda1168db848cb74 100644
--- a/chrome/browser/autofill/autofill_manager.h
+++ b/chrome/browser/autofill/autofill_manager.h
@@ -17,6 +17,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "base/string16.h"
+#include "base/time.h"
 #include "chrome/browser/autofill/autofill_download.h"
 #include "chrome/browser/autofill/field_types.h"
 #include "chrome/browser/autofill/form_structure.h"
@@ -113,10 +114,12 @@ class AutofillManager : public TabContentsObserver,
   void UnpackGUIDs(int id, GUIDPair* cc_guid, GUIDPair* profile_guid);
 
  private:
-  void OnFormSubmitted(const webkit_glue::FormData& form);
+  void OnFormSubmitted(const webkit_glue::FormData& form,
+                       const base::TimeTicks& timestamp);
   void OnFormsSeen(const std::vector<webkit_glue::FormData>& forms);
   void OnTextFieldDidChange(const webkit_glue::FormData& form,
-                            const webkit_glue::FormField& field);
+                            const webkit_glue::FormField& field,
+                            const base::TimeTicks& timestamp);
   void OnQueryFormFieldAutofill(int query_id,
                                 const webkit_glue::FormData& form,
                                 const webkit_glue::FormField& field);
@@ -126,7 +129,7 @@ class AutofillManager : public TabContentsObserver,
                               int unique_id);
   void OnShowAutofillDialog();
   void OnDidPreviewAutofillFormData();
-  void OnDidFillAutofillFormData();
+  void OnDidFillAutofillFormData(const base::TimeTicks& timestamp);
   void OnDidShowAutofillSuggestions(bool is_new_popup);
 
   // Fills |host| with the RenderViewHost for this tab.
@@ -233,6 +236,9 @@ class AutofillManager : public TabContentsObserver,
   bool user_did_autofill_;
   // Has the user edited a field that was previously autofilled?
   bool user_did_edit_autofilled_field_;
+  // When the user first interacted with a potentially fillable form on this
+  // page.
+  base::TimeTicks initial_interaction_timestamp_;
 
   // Our copy of the form data.
   ScopedVector<FormStructure> form_structures_;
@@ -277,6 +283,7 @@ class AutofillManager : public TabContentsObserver,
   FRIEND_TEST_ALL_PREFIXES(AutofillMetricsTest,
                            UserHappinessFormLoadAndSubmission);
   FRIEND_TEST_ALL_PREFIXES(AutofillMetricsTest, UserHappinessFormInteraction);
+  FRIEND_TEST_ALL_PREFIXES(AutofillMetricsTest, FormFillDuration);
 
   DISALLOW_COPY_AND_ASSIGN(AutofillManager);
 };