[Autofill Assistant] Prevent overlay in lite scripts.

Lite scripts should never show the overlay. This is achieved in two
steps:

- Auto-insert a ConfigureUiState action as the first action to run.
- Blacklist ConfigureUiState, such that scripts can't override this.

Bug: b/164506953
Change-Id: Ibce93307e2f8fd3ef15bb1aeb0b2e338b0e48457
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2362822Reviewed-by: Mathias Carlen <mcarlen@chromium.org>
Commit-Queue: Clemens Arbesser <arbesser@google.com>
Cr-Commit-Position: refs/heads/master@{#800138}

components/autofill_assistant/browser/lite_service.cc

@@ -115,6 +115,15 @@ void LiteService::OnGetActions(ResponseCallback callback,
   // order to map the chosen payload back to the action it originated from.
   lite_service_util::AssignUniquePayloadsToPrompts(&response_proto);
 
+  // Prepend a ConfigureUi action to ensure that the overlay will not be shown.
+  ActionProto configure_ui;
+  configure_ui.mutable_configure_ui_state()->set_overlay_behavior(
+      ConfigureUiStateProto::HIDDEN);
+  *response_proto.add_actions() = configure_ui;
+  for (int i = response_proto.actions().size() - 1; i > 0; --i) {
+    response_proto.mutable_actions()->SwapElements(i, i - 1);
+  }
+
   auto split_actions =
       lite_service_util::SplitActionsAtLastBrowse(response_proto);
   if (!split_actions.has_value()) {

components/autofill_assistant/browser/lite_service_unittest.cc

@@ -229,15 +229,21 @@ TEST_F(LiteServiceTest, GetActionsSplitsActionsResponseAtLastBrowse) {
         // will have automatically assigned unique payloads to prompts.
         ActionsResponseProto proto;
         ASSERT_TRUE(proto.ParseFromString(response));
-        ASSERT_TRUE(proto.actions().size() == 3);
+        ASSERT_TRUE(proto.actions().size() == 4);
+        // The first action is a ConfigureUiState, which is automatically added
+        // by the lite_service.
         EXPECT_TRUE(proto.actions(0).action_info_case() ==
-                    ActionProto::kPrompt);
-        EXPECT_TRUE(proto.actions(0).prompt().browse_mode());
+                    ActionProto::kConfigureUiState);
+        EXPECT_TRUE(proto.actions(0).configure_ui_state().overlay_behavior() ==
+                    ConfigureUiStateProto::HIDDEN);
         EXPECT_TRUE(proto.actions(1).action_info_case() ==
-                    ActionProto::kWaitForDom);
+                    ActionProto::kPrompt);
+        EXPECT_TRUE(proto.actions(1).prompt().browse_mode());
         EXPECT_TRUE(proto.actions(2).action_info_case() ==
+                    ActionProto::kWaitForDom);
+        EXPECT_TRUE(proto.actions(3).action_info_case() ==
                     ActionProto::kPrompt);
-        EXPECT_TRUE(proto.actions(2).prompt().browse_mode());
+        EXPECT_TRUE(proto.actions(3).prompt().browse_mode());
 
         for (const auto& action : proto.actions()) {
           processed_actions.emplace_back(ProcessedActionProto());
@@ -245,7 +251,7 @@ TEST_F(LiteServiceTest, GetActionsSplitsActionsResponseAtLastBrowse) {
           processed_actions.back().set_status(ACTION_APPLIED);
         }
         processed_actions.back().mutable_prompt_choice()->set_server_payload(
-            proto.actions(2).prompt().choices(0).server_payload());
+            proto.actions(3).prompt().choices(0).server_payload());
       });
   lite_service_->GetActions(kFakeScriptPath, GURL(kFakeUrl),
                             TriggerContextImpl(), "", "",

components/autofill_assistant/browser/lite_service_util.cc

@@ -29,8 +29,7 @@ const ActionProto::ActionInfoCase kAllowedActions[] = {
     ActionProto::kWaitForNavigation,
     ActionProto::kConfigureBottomSheet,
     ActionProto::kPopupMessage,
-    ActionProto::kWaitForDocument,
-    ActionProto::kConfigureUiState};
+    ActionProto::kWaitForDocument};
 
 base::Optional<std::pair<ActionsResponseProto, ActionsResponseProto>>
 SplitActionsAtLastBrowse(const ActionsResponseProto& proto) {

components/autofill_assistant/browser/lite_service_util_unittest.cc

@@ -103,7 +103,6 @@ TEST(LiteServiceUtilTest, ContainsOnlySafeActions) {
   safe_actions.add_actions()->mutable_configure_bottom_sheet();
   safe_actions.add_actions()->mutable_popup_message();
   safe_actions.add_actions()->mutable_wait_for_document();
-  safe_actions.add_actions()->mutable_configure_ui_state();
 
   EXPECT_TRUE(ContainsOnlySafeActions(safe_actions));
 
@@ -125,6 +124,7 @@ TEST(LiteServiceUtilTest, ContainsOnlySafeActions) {
   unsafe_actions.add_actions()->mutable_generate_password_for_form_field();
   unsafe_actions.add_actions()->mutable_save_generated_password();
   unsafe_actions.add_actions()->mutable_presave_generated_password();
+  unsafe_actions.add_actions()->mutable_configure_ui_state();
   for (const auto& unsafe_action : unsafe_actions.actions()) {
     ActionsResponseProto test_actions = safe_actions;
     *test_actions.add_actions() = unsafe_action;