[Autofill] Enable Autofill for dynamically created forms.

components/autofill/content/renderer/autofill_agent.h

Index: components/autofill/content/renderer/autofill_agent.h
diff --git a/components/autofill/content/renderer/autofill_agent.h b/components/autofill/content/renderer/autofill_agent.h
index 5b268d9fdfea42dc6f3de494de468db26723586d..0596ca1193f5d687dfc418bdd0a5561b730ee520 100644
--- a/components/autofill/content/renderer/autofill_agent.h
+++ b/components/autofill/content/renderer/autofill_agent.h
@@ -15,7 +15,6 @@
 #include "base/timer/timer.h"
 #include "components/autofill/content/renderer/form_cache.h"
 #include "components/autofill/content/renderer/page_click_listener.h"
-#include "components/autofill/core/common/forms_seen_state.h"
 #include "content/public/renderer/render_view_observer.h"
 #include "third_party/WebKit/public/web/WebAutofillClient.h"
 #include "third_party/WebKit/public/web/WebFormControlElement.h"
@@ -165,6 +164,9 @@ class AutofillAgent : public content::RenderViewObserver,
   void PreviewFieldWithValue(const base::string16& value,
                              blink::WebInputElement* node);
 
+  // Notifies browser of new fillable forms in |frame|.
+  void ProcessForms(const blink::WebLocalFrame& frame);
+
   // Hides any currently showing Autofill popup.
   void HidePopup();
 
@@ -216,8 +218,10 @@ class AutofillAgent : public content::RenderViewObserver,
   // messages to close the Autofill popup when it can't possibly be showing.
   bool is_popup_possibly_visible_;
 
-  // Timestamp of first time forms are seen.
-  base::TimeTicks forms_seen_timestamp_;
+  // True if a message has already been sent about forms for the main frame.
+  // When the main frame is first loaded, a message is sent even if no forms
+  // exist in the frame. Otherwise, such messages are supressed.
+  bool main_frame_processed_;
 
   base::WeakPtrFactory<AutofillAgent> weak_ptr_factory_;