[Autofill] Migrate ContentAutofillDriver<-->AutofillAgent IPCs to mojo.

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 8cb3dc463bf8d47172344f2132f35a45afd3aaef..bd46a9c3d4edb30e7b350d5758786a8502407a9f 100644
--- a/components/autofill/content/renderer/autofill_agent.cc
+++ b/components/autofill/content/renderer/autofill_agent.cc
@@ -205,7 +205,6 @@ bool AutofillAgent::FormDataCompare::operator()(const FormData& lhs,
 bool AutofillAgent::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(AutofillAgent, message)
-    IPC_MESSAGE_HANDLER(AutofillMsg_FillForm, OnFillForm)
     IPC_MESSAGE_HANDLER(AutofillMsg_PreviewForm, OnPreviewForm)
     IPC_MESSAGE_HANDLER(AutofillMsg_FieldTypePredictionsAvailable,
                         OnFieldTypePredictionsAvailable)
@@ -507,8 +506,15 @@ void AutofillAgent::OnFieldTypePredictionsAvailable(
   }
 }
 
-void AutofillAgent::OnFillForm(int query_id, const FormData& form) {
-  if (query_id != autofill_query_id_)
+// mojom::AutofillAgent:
+void AutofillAgent::FirstUserGestureObservedInTab() {
+  password_autofill_agent_->FirstUserGestureObserved();
+}
+
+void AutofillAgent::FillForm(int32_t id,
+                             const FormData& form,
+                             const FillFormCallback& callback) {
+  if (id != autofill_query_id_)
     return;
 
   was_query_node_autofilled_ = element_.isAutofilled();
@@ -516,13 +522,7 @@ void AutofillAgent::OnFillForm(int query_id, const FormData& form) {
   if (!element_.form().isNull())
     last_interacted_form_ = element_.form();
 
-  Send(new AutofillHostMsg_DidFillAutofillFormData(routing_id(), form,
-                                                   base::TimeTicks::Now()));
-}
-
-// mojom::AutofillAgent:
-void AutofillAgent::FirstUserGestureObservedInTab() {
-  password_autofill_agent_->FirstUserGestureObserved();
+  callback.Run(form, base::TimeTicks::Now().ToInternalValue());
 }
 
 void AutofillAgent::OnPing() {