Requery the autofill server when forms and input fields are dynamically added.

components/autofill/browser/autofill_manager.cc

Index: components/autofill/browser/autofill_manager.cc
diff --git a/components/autofill/browser/autofill_manager.cc b/components/autofill/browser/autofill_manager.cc
index 3db909be9cc945cfbf022a187e50ae246b2f082c..a13ada31809bcf7482ae7ac544bff0f9f20a3204 100644
--- a/components/autofill/browser/autofill_manager.cc
+++ b/components/autofill/browser/autofill_manager.cc
@@ -448,14 +448,22 @@ bool AutofillManager::OnFormSubmitted(const FormData& form,
 
 void AutofillManager::OnFormsSeen(const std::vector<FormData>& forms,
                                   const TimeTicks& timestamp,
-                                  bool has_more_forms) {
+                                  autofill::FormsSeenParam param) {
+  bool is_post_document_load = param & autofill::DYNAMIC_FORMS_SEEN;
+  bool has_more_forms = param & autofill::PARTIAL_FORMS_SEEN;

[Ilya Sherman, 2013/04/06 00:29:39]

Since you're using this as a bitmask, please define the enum constants as
bitshifts.

[Dane Wallinga, 2013/04/08 22:55:50]

Done.

+  // If new forms were added via AJAX or DHML, treat as new page.
+  if (is_post_document_load)
+    Reset();

[Ilya Sherman, 2013/04/06 00:29:39]

What happens if the user is already interacting with the page?  Will this do the
right thing?  If so, why?

[Dane Wallinga, 2013/04/08 22:55:50]

Hmm, that depends very much on what we think the 'right thing' is. The page will
be treated as though it's a new page. For the purposes of correctly filling out
an ajaxy flow, that's what we want. For the purposes of recording metrics (and
it's mostly metric related vars that get reset in that call) it's less clear. If
most of the page changes, then it makes sense to count it is a new page. If it's
just a new field that pops up, maybe not. If absolutely necessary, we could
probably add more nuance to the metrics we're logging to distinguish these types
of flows, but I don't know exactly how we'd want to structure that.

[Ilya Sherman, 2013/04/09 02:17:46]

Reset() also throws away the list of form_structures_, which means that we lose
any server-side data that we might have had for these in the case that just a
field or two was changed.  Note that this is not actually that rare a case:
websites will often change the form fields that are shown based on the user's
choice of country from a dropdown (e.g. should a "state" field be shown?).

Maybe that's ok, though, since the server will tend to have data for forms as
they look when they're submitted, rather than when they're loaded.

[Dane Wallinga, 2013/04/10 00:19:13]

If we don't throw the list of form_structures_ away, then the post-ajax forms
just get appended which results in duplicates, and then the mappings back from
the server don't line up properly with the form_structures_, and all manner of
annoying things can happen. As you say, though - the autofill server is going to
have data based on the submitted state, which will probably include any dom
changes.

+
   RenderViewHost* host = web_contents()->GetRenderViewHost();
   if (!host)
     return;
 
   if (!GetAutocheckoutURLPrefix().empty()) {
-    host->Send(
-        new AutofillMsg_WhitelistedForAutocheckout(host->GetRoutingID()));
+    if (!is_post_document_load) {
+      host->Send(
+          new AutofillMsg_WhitelistedForAutocheckout(host->GetRoutingID()));
+    }
     // If whitelisted URL, fetch all the forms.
     if (has_more_forms) {
       host->Send(new AutofillMsg_GetAllForms(host->GetRoutingID()));