[Autofill Assistant] Introduce a TabHelper.

The Autofill Assistant stack's lifecycle is not using Chrome's framework
designed to provide exactly that. This patch introduces a TabHelper that
will become a proper entry point to control construction and destruction
of components of the Autofill Assistant stack that depend on a WebContents.

This initial patch only adds an empty TabHelper and test and hooks it up in the
tab_helpers registry behind a default disabled AutofillAssistantTabHelpers
feature.

Bug: b/169389571
Change-Id: I3129fd04e5e4dd6c65c1df891383cf29cad508d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2521620
Commit-Queue: Mathias Carlen <mcarlen@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825719}

chrome/browser/ui/BUILD.gn

@@ -652,6 +652,8 @@ static_library("ui") {
       "android/autofill/card_unmask_prompt_view_android.h",
       "android/autofill/credit_card_scanner_view_android.cc",
       "android/autofill/credit_card_scanner_view_android.h",
+      "android/autofill_assistant/autofill_assistant_tab_helper.cc",
+      "android/autofill_assistant/autofill_assistant_tab_helper.h",
       "android/chrome_http_auth_handler.cc",
       "android/chrome_http_auth_handler.h",
       "android/chrome_javascript_app_modal_dialog_android.cc",
@@ -795,6 +797,8 @@ static_library("ui") {
       "//chrome/android/features/dev_ui:buildflags",
       "//chrome/browser/image_decoder",
       "//chrome/browser/resources/webapks:webapks_ui_resources",
+      "//components/autofill_assistant/browser",
+      "//components/autofill_assistant/browser:proto",
       "//components/browser_ui/client_certificate/android",
       "//components/embedder_support/android:browser_context",
       "//components/embedder_support/android:context_menu",

chrome/browser/ui/android/autofill_assistant/OWNERS

+file://components/autofill_assistant/OWNERS

chrome/browser/ui/android/autofill_assistant/autofill_assistant_tab_helper.cc

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/ui/android/autofill_assistant/autofill_assistant_tab_helper.h"
+
+#include "base/time/default_tick_clock.h"
+
+namespace autofill_assistant {
+
+AutofillAssistantTabHelper::~AutofillAssistantTabHelper() {}
+
+void AutofillAssistantTabHelper::WebContentsDestroyed() {}
+
+AutofillAssistantTabHelper::AutofillAssistantTabHelper(
+    content::WebContents* web_contents)
+    : content::WebContentsObserver(web_contents) {}
+
+WEB_CONTENTS_USER_DATA_KEY_IMPL(AutofillAssistantTabHelper)
+
+}  // namespace autofill_assistant

chrome/browser/ui/android/autofill_assistant/autofill_assistant_tab_helper.h

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_UI_ANDROID_AUTOFILL_ASSISTANT_AUTOFILL_ASSISTANT_TAB_HELPER_H_
+#define CHROME_BROWSER_UI_ANDROID_AUTOFILL_ASSISTANT_AUTOFILL_ASSISTANT_TAB_HELPER_H_
+
+#include "components/autofill_assistant/browser/controller.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/browser/web_contents_user_data.h"
+
+namespace autofill_assistant {
+
+// AutofillAssistantTabHelper for the AutofillAssistant component.
+class AutofillAssistantTabHelper
+    : public content::WebContentsUserData<AutofillAssistantTabHelper>,
+      public content::WebContentsObserver {
+ public:
+  ~AutofillAssistantTabHelper() override;
+  AutofillAssistantTabHelper(const AutofillAssistantTabHelper&) = delete;
+  AutofillAssistantTabHelper& operator=(const AutofillAssistantTabHelper&) =
+      delete;
+
+  // content::WebContentsObserver:
+  void WebContentsDestroyed() override;
+
+ private:
+  friend class content::WebContentsUserData<AutofillAssistantTabHelper>;
+  explicit AutofillAssistantTabHelper(content::WebContents* web_contents);
+
+  WEB_CONTENTS_USER_DATA_KEY_DECL();
+};
+
+}  // namespace autofill_assistant
+
+#endif  // CHROME_BROWSER_UI_ANDROID_AUTOFILL_ASSISTANT_AUTOFILL_ASSISTANT_TAB_HELPER_H_

chrome/browser/ui/android/autofill_assistant/autofill_assistant_tab_helper_unittest.cc

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/ui/android/autofill_assistant/autofill_assistant_tab_helper.h"
+
+#include "chrome/test/base/chrome_render_view_host_test_harness.h"
+#include "chrome/test/base/testing_profile.h"
+#include "content/public/browser/web_contents.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace autofill_assistant {
+namespace {
+
+class AutofillAssistantTabHelperTest : public ChromeRenderViewHostTestHarness {
+ public:
+  AutofillAssistantTabHelperTest();
+  ~AutofillAssistantTabHelperTest() override {}
+
+  void SetUp() override;
+
+  AutofillAssistantTabHelper* tab_helper() const { return tab_helper_; }
+
+ private:
+  AutofillAssistantTabHelper* tab_helper_;  // Owned by WebContents.
+};
+
+AutofillAssistantTabHelperTest::AutofillAssistantTabHelperTest()
+    : tab_helper_(nullptr) {}
+
+void AutofillAssistantTabHelperTest::SetUp() {
+  ChromeRenderViewHostTestHarness::SetUp();
+
+  AutofillAssistantTabHelper::CreateForWebContents(web_contents());
+  tab_helper_ = AutofillAssistantTabHelper::FromWebContents(web_contents());
+}
+
+// Checks the test setup.
+TEST_F(AutofillAssistantTabHelperTest, InitialSetup) {
+  EXPECT_NE(nullptr, tab_helper());
+}
+
+}  // namespace
+}  // namespace autofill_assistant

chrome/browser/ui/tab_helpers.cc

@@ -120,9 +120,11 @@
 #include "chrome/browser/android/search_permissions/search_geolocation_disclosure_tab_helper.h"
 #include "chrome/browser/banners/app_banner_manager_android.h"
 #include "chrome/browser/flags/android/chrome_feature_list.h"
+#include "chrome/browser/ui/android/autofill_assistant/autofill_assistant_tab_helper.h"
 #include "chrome/browser/ui/android/context_menu_helper.h"
 #include "chrome/browser/ui/javascript_dialogs/javascript_tab_modal_dialog_manager_delegate_android.h"
 #include "chrome/browser/video_tutorials/video_tutorial_tab_helper.h"
+#include "components/autofill_assistant/browser/features.h"
 #else
 #include "chrome/browser/banners/app_banner_manager_desktop.h"
 #include "chrome/browser/tab_contents/form_interaction_tab_helper.h"
@@ -354,6 +356,11 @@ void TabHelpers::AttachTabHelpers(WebContents* web_contents) {
   }
   SearchGeolocationDisclosureTabHelper::CreateForWebContents(web_contents);
   video_tutorials::VideoTutorialTabHelper::CreateForWebContents(web_contents);
+  if (base::FeatureList::IsEnabled(
+          autofill_assistant::features::kAutofillAssistantWithTabHelper)) {
+    autofill_assistant::AutofillAssistantTabHelper::CreateForWebContents(
+        web_contents);
+  }
 #else
   banners::AppBannerManagerDesktop::CreateForWebContents(web_contents);
   BookmarkTabHelper::CreateForWebContents(web_contents);

chrome/test/BUILD.gn

@@ -3864,6 +3864,7 @@ test("unit_tests") {
       "../browser/notifications/notification_channels_provider_android_unittest.cc",
       "../browser/search/contextual_search_policy_handler_android_unittest.cc",
       "../browser/translate/android/translate_bridge_unittest.cc",
+      "../browser/ui/android/autofill_assistant/autofill_assistant_tab_helper_unittest.cc",
       "../browser/ui/android/tab_model/tab_model_list_unittest.cc",
       "../browser/ui/android/toolbar/location_bar_model_android_unittest.cc",
     ]