First pass at refactoring autofill_agent to eventually incorporate Synthetic Form logic.

components/autofill/content/renderer/autofill_agent.cc

Index: components/autofill/content/renderer/autofill_agent.cc
diff --git a/components/autofill/content/renderer/autofill_agent.cc b/components/autofill/content/renderer/autofill_agent.cc
index 8ee04e6429f6a4c908d2d6e295ed8056e5a7a9e2..2261252d7f3c63929b2ec4edf278ddf6013fbc15 100644
--- a/components/autofill/content/renderer/autofill_agent.cc
+++ b/components/autofill/content/renderer/autofill_agent.cc
@@ -248,36 +248,11 @@ void AutofillAgent::DidFinishDocumentLoad() {
 }
 
 void AutofillAgent::WillSendSubmitEvent(const WebFormElement& form) {
-  FormData form_data;
-  if (!form_util::ExtractFormData(form, &form_data))
-    return;
-
-  // The WillSendSubmitEvent function is called when there is a submit handler
-  // on the form, such as in the case of (but not restricted to)
-  // JavaScript-submitted forms. Sends a WillSubmitForm message to the browser
-  // and remembers for which form it did that in the current frame load, so that
-  // no additional message is sent if AutofillAgent::WillSubmitForm() is called
-  // (which is itself not guaranteed if the submit event is prevented by
-  // JavaScript).
-  if (!submitted_forms_.count(form_data)) {
-    Send(new AutofillHostMsg_WillSubmitForm(routing_id(), form_data,
-                                            base::TimeTicks::Now()));
-    submitted_forms_.insert(form_data);
-  }
+  FireHostSubmitEvents(form, true, false);

[Mathieu, 2016/05/25 17:48:55]

nit: FireHostSubmitEvents(form, /* form_submitted= */ false);

I find this style easier for the reader.

[tmartino, 2016/05/25 18:39:42]

Agreed, done.

 }
 
 void AutofillAgent::WillSubmitForm(const WebFormElement& form) {
-  FormData form_data;
-  if (!form_util::ExtractFormData(form, &form_data))
-    return;
-
-  // If WillSubmitForm message had not been sent for this form, send it.
-  if (!submitted_forms_.count(form_data)) {
-    Send(new AutofillHostMsg_WillSubmitForm(routing_id(), form_data,
-                                            base::TimeTicks::Now()));
-  }
-
-  Send(new AutofillHostMsg_FormSubmitted(routing_id(), form_data));
+  FireHostSubmitEvents(form, true, true);
 }
 
 void AutofillAgent::DidChangeScrollOffset() {
@@ -322,6 +297,33 @@ void AutofillAgent::OnDestruct() {
   base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, this);
 }
 
+void AutofillAgent::FireHostSubmitEvents(const WebFormElement& form,
+                                         bool willSubmitForm,
+                                         bool formSubmitted) {
+  FormData form_data;
+  if (!form_util::ExtractFormData(form, &form_data)) {
+    return;
+  }
+  FireHostSubmitEvents(form_data, willSubmitForm, formSubmitted);
+}
+
+void AutofillAgent::FireHostSubmitEvents(const FormData& form_data,
+                                         bool willSubmitForm,
+                                         bool formSubmitted) {
+  // We remember when we have fired this IPC for this form in this frame load,
+  // because forms with a submit handler may fire both WillSendSubmitEvent
+  // and WillSubmitForm, and we don't want duplicate messages.
+  if (willSubmitForm && !submitted_forms_.count(form_data)) {
+    Send(new AutofillHostMsg_WillSubmitForm(routing_id(), form_data,
+                                            base::TimeTicks::Now()));
+    submitted_forms_.insert(form_data);
+  }
+
+  if (formSubmitted) {
+    Send(new AutofillHostMsg_FormSubmitted(routing_id(), form_data));
+  }
+}
+
 void AutofillAgent::Shutdown() {
   legacy_.Shutdown();
   weak_ptr_factory_.InvalidateWeakPtrs();
@@ -597,18 +599,18 @@ void AutofillAgent::OnPreviewPasswordSuggestion(
 }
 
 void AutofillAgent::OnSamePageNavigationCompleted() {
-  if (last_interacted_form_.isNull())
+  if (last_interacted_form_.isNull()) {
+    // TODO(tmartino): Try using Synthetic Form from form_cache.
     return;
-
-  // Assume form submission only if the form is now gone, either invisible or
-  // removed from the DOM.
-  if (form_util::AreFormContentsVisible(last_interacted_form_))
-    return;
-
-  // Could not find a visible form equal to our saved form, assume submission.
-  WillSendSubmitEvent(last_interacted_form_);
-  WillSubmitForm(last_interacted_form_);
-  last_interacted_form_.reset();
+  } else {

[Mathieu, 2016/05/25 17:48:55]

nit: don't need an else if you return in the above "if" block

[tmartino, 2016/05/25 18:39:42]

Done.

+    // Assume form submission only if the form is now gone, either invisible or
+    // removed from the DOM.
+    if (form_util::AreFormContentsVisible(last_interacted_form_)) {
+      return;
+    }
+    FireHostSubmitEvents(last_interacted_form_, true, true);
+    last_interacted_form_.reset();
+  }
 }
 
 void AutofillAgent::ShowSuggestions(const WebFormControlElement& element,