Autofill: Set requirements for number of recognized fields in an autofillable form

components/autofill/content/renderer/form_cache.cc

Index: components/autofill/content/renderer/form_cache.cc
diff --git a/components/autofill/content/renderer/form_cache.cc b/components/autofill/content/renderer/form_cache.cc
index 9bc97e2f5505c598566d3a66b4995d9839aa2dd4..0b9bc8abbfeae00bc27039882cd8c1e2550d1dc6 100644
--- a/components/autofill/content/renderer/form_cache.cc
+++ b/components/autofill/content/renderer/form_cache.cc
@@ -75,7 +75,10 @@ FormCache::FormCache(const WebFrame& frame) : frame_(frame) {
 FormCache::~FormCache() {
 }
 
-std::vector<FormData> FormCache::ExtractNewForms() {
+std::vector<FormData> FormCache::ExtractNewForms(size_t* unowned_form_index) {
+  DCHECK(unowned_form_index);
+
+  *unowned_form_index = 0;
   std::vector<FormData> forms;
   WebDocument document = frame_.document();
   if (document.isNull())
@@ -115,6 +118,7 @@ std::vector<FormData> FormCache::ExtractNewForms() {
 
     if (form.fields.size() >= kRequiredAutofillFields &&
         !ContainsKey(parsed_forms_, form)) {
+      ++(*unowned_form_index);
       forms.push_back(form);
       parsed_forms_.insert(form);
     }
@@ -145,6 +149,7 @@ std::vector<FormData> FormCache::ExtractNewForms() {
 
   if (synthetic_form.fields.size() >= kRequiredAutofillFields &&
       !parsed_forms_.count(synthetic_form)) {
+    // |*unowned_form_index| is already at the right index here.
     forms.push_back(synthetic_form);
     parsed_forms_.insert(synthetic_form);
     synthetic_form_ = synthetic_form;