[Extensions] Add chrome.loginScreenUi API

This CL adds a new extension API "loginScreenUi", which can be used to
display custom UI on the login screen. The generated window will only
be visible on the login and lock screen.
This API will only be available to whitelisted extensions of type
"login_screen_extension".

API proposal: go/api-login-screen-ui
Design doc: go/dd-login-screen-extension-ui

Bug: 957573
Change-Id: Ie9f936af9fd21e9b324f5bbbd8448790f8d33c4d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1556806
Commit-Queue: Alexander Hendrich <hendrich@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664501}

chrome/app/generated_resources.grd

@@ -3673,6 +3673,9 @@ are declared in tools/grit/grit_rule.gni.
         <message name="IDS_EXTENSION_PROMPT_WARNING_INPUT" desc="Permission string for access to input.">
           Read and change anything you type
         </message>
+        <message name="IDS_EXTENSION_PROMPT_WARNING_LOGIN_SCREEN_UI" desc="Permission string for access to login screen UI.">
+          Display UI on the login screen
+        </message>
         <message name="IDS_EXTENSION_PROMPT_WARNING_MANAGEMENT" desc="Permisson string for access to extension management.">
           Manage your apps, extensions, and themes
         </message>

chrome/browser/chromeos/BUILD.gn

@@ -2089,6 +2089,8 @@ source_set("chromeos") {
     "extensions/input_method_api.h",
     "extensions/login_screen_ui/login_screen_extension_ui_handler.cc",
     "extensions/login_screen_ui/login_screen_extension_ui_handler.h",
+    "extensions/login_screen_ui/login_screen_ui_api.cc",
+    "extensions/login_screen_ui/login_screen_ui_api.h",
     "extensions/media_player_api.cc",
     "extensions/media_player_api.h",
     "extensions/quick_unlock_private/quick_unlock_private_api.cc",

chrome/browser/chromeos/extensions/login_screen_ui/login_screen_extension_ui_handler.cc

@@ -9,11 +9,13 @@
 #include "ash/public/cpp/login_types.h"
 #include "chrome/browser/chromeos/login/ui/login_screen_extension_ui/login_screen_extension_ui_window.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
+#include "chrome/browser/ui/ash/login_screen_client.h"
 #include "components/session_manager/core/session_manager.h"
 #include "content/public/browser/browser_thread.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/common/constants.h"
 #include "extensions/common/extension.h"
+#include "extensions/common/permissions/permissions_data.h"
 
 namespace chromeos {
 
@@ -28,10 +30,11 @@ const char kErrorNotOnLoginOrLockScreen[] =
 LoginScreenExtensionUiHandler* g_instance = nullptr;
 
 bool CanUseLoginScreenUiApi(const extensions::Extension* extension) {
-  // TODO(hendrich) also check permission in CL 1556806
   return extensions::ExtensionRegistry::Get(ProfileHelper::GetSigninProfile())
-      ->enabled_extensions()
-      .Contains(extension->id());
+             ->enabled_extensions()
+             .Contains(extension->id()) &&
+         extension->permissions_data()->HasAPIPermission(
+             extensions::APIPermission::kLoginScreenUi);
 }
 
 }  // namespace

chrome/browser/chromeos/extensions/login_screen_ui/login_screen_extension_ui_handler_unittest.cc

@@ -13,11 +13,13 @@
 #include "chrome/test/base/testing_browser_process.h"
 #include "chrome/test/base/testing_profile_manager.h"
 #include "components/session_manager/core/session_manager.h"
+#include "components/version_info/version_info.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "content/public/test/test_service_manager_context.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/extension_builder.h"
+#include "extensions/common/features/feature_channel.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
@@ -31,6 +33,12 @@ const char kErrorNotOnLoginOrLockScreen[] =
 const bool kCanBeClosedByUser = false;
 const char kUrl[] = "test.html";
 
+const char kWhitelistedExtensionID1[] =
+    "oclffehlkdgibkainkilopaalpdobkan";  // chrome.loginScreenUi test extension
+const char kWhitelistedExtensionID2[] =
+    "lpimkpkllnkdlcigdbgmabfplniahkgm";  // Imprivata (login screen)
+const char kPermissionName[] = "loginScreenUi";
+
 }  // namespace
 
 namespace chromeos {
@@ -83,7 +91,8 @@ class FakeLoginScreenExtensionUiWindowFactory
 class LoginScreenExtensionUiHandlerUnittest : public testing::Test {
  public:
   LoginScreenExtensionUiHandlerUnittest()
-      : profile_manager_(TestingBrowserProcess::GetGlobal()) {}
+      : scoped_current_channel_(version_info::Channel::DEV),
+        profile_manager_(TestingBrowserProcess::GetGlobal()) {}
   ~LoginScreenExtensionUiHandlerUnittest() override = default;
 
   void SetUp() override {
@@ -107,7 +116,10 @@ class LoginScreenExtensionUiHandlerUnittest : public testing::Test {
         session_manager::SessionState::LOGIN_PRIMARY);
 
     extension_ = extensions::ExtensionBuilder("test" /*extension_name*/)
-                     .SetID("abcdefghijklmnopqrstuvwxyzabcdef")
+                     .SetID(kWhitelistedExtensionID1)
+                     .SetLocation(extensions::Manifest::EXTERNAL_POLICY)
+                     .AddPermission(kPermissionName)
+                     .AddFlags(extensions::Extension::FOR_LOGIN_SCREEN)
                      .Build();
     extension_registry_->AddEnabled(extension_);
   }
@@ -169,6 +181,7 @@ class LoginScreenExtensionUiHandlerUnittest : public testing::Test {
 
   content::TestBrowserThreadBundle thread_bundle_;
   content::TestServiceManagerContext context_;
+  const extensions::ScopedCurrentChannel scoped_current_channel_;
 
   session_manager::SessionManager session_manager_;
   TestingProfileManager profile_manager_;
@@ -264,7 +277,10 @@ TEST_F(LoginScreenExtensionUiHandlerUnittest, WindowClosedOnUnlock) {
 TEST_F(LoginScreenExtensionUiHandlerUnittest, TwoExtensionsInParallel) {
   scoped_refptr<const extensions::Extension> other_extension =
       extensions::ExtensionBuilder("other extension" /*extension_name*/)
-          .SetID("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")
+          .SetID(kWhitelistedExtensionID2)
+          .SetLocation(extensions::Manifest::EXTERNAL_POLICY)
+          .AddPermission(kPermissionName)
+          .AddFlags(extensions::Extension::FOR_LOGIN_SCREEN)
           .Build();
   extension_registry_->AddEnabled(other_extension);
 
@@ -329,16 +345,32 @@ TEST_F(LoginScreenExtensionUiHandlerUnittest,
   EXPECT_TRUE(ui_handler_->HasOpenWindow(extension_->id()));
 }
 
-TEST_F(LoginScreenExtensionUiHandlerDeathUnittest, NotFromSigninProfile) {
-  // |other_extension| is not enabled in the sign-in profile's extensions
-  // registry.
-  scoped_refptr<const extensions::Extension> other_extension =
-      extensions::ExtensionBuilder("other extension" /*extension_name*/)
-          .SetID("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb")
+TEST_F(LoginScreenExtensionUiHandlerDeathUnittest, NotAllowed) {
+  // |other_profile_extension| is not enabled in the sign-in profile's
+  // extensions registry.
+  scoped_refptr<const extensions::Extension> other_profile_extension =
+      extensions::ExtensionBuilder("other profile" /*extension_name*/)
+          .SetID(kWhitelistedExtensionID2)  // whitelisted
+          .SetLocation(extensions::Manifest::EXTERNAL_POLICY)
+          .AddPermission(kPermissionName)
+          .AddFlags(extensions::Extension::FOR_LOGIN_SCREEN)
+          .Build();
+
+  CheckCannotUseAPI(other_profile_extension.get());
+  CheckCannotUseAPI(other_profile_extension.get());
+
+  // |no_permission_extension| is enabled in the sign-in profile's extensions
+  // registry, but doesn't have the needed "loginScreenUi" permission.
+  scoped_refptr<const extensions::Extension> no_permission_extension =
+      extensions::ExtensionBuilder("no permission extension" /*extension_name*/)
+          .SetID(kWhitelistedExtensionID2)  // whitelisted
+          .SetLocation(extensions::Manifest::EXTERNAL_POLICY)
+          .AddFlags(extensions::Extension::FOR_LOGIN_SCREEN)
           .Build();
+  extension_registry_->AddEnabled(no_permission_extension);
 
-  CheckCannotUseAPI(other_extension.get());
-  CheckCannotUseAPI(other_extension.get());
+  CheckCannotUseAPI(no_permission_extension.get());
+  CheckCannotUseAPI(no_permission_extension.get());
 }
 
 }  // namespace chromeos

chrome/browser/chromeos/extensions/login_screen_ui/login_screen_ui_api.cc

+// Copyright 2019 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/chromeos/extensions/login_screen_ui/login_screen_ui_api.h"
+
+#include "chrome/browser/chromeos/extensions/login_screen_ui/login_screen_extension_ui_handler.h"
+#include "chrome/common/extensions/api/login_screen_ui.h"
+
+namespace login_screen_ui = extensions::api::login_screen_ui;
+
+namespace extensions {
+
+LoginScreenUiShowFunction::LoginScreenUiShowFunction() = default;
+LoginScreenUiShowFunction::~LoginScreenUiShowFunction() = default;
+
+ExtensionFunction::ResponseAction LoginScreenUiShowFunction::Run() {
+  std::unique_ptr<login_screen_ui::Show::Params> parameters =
+      login_screen_ui::Show::Params::Create(*args_);
+  EXTENSION_FUNCTION_VALIDATE(parameters);
+
+  const login_screen_ui::ShowOptions& options = parameters->options;
+  bool user_can_close =
+      options.user_can_close ? *options.user_can_close : false;
+
+  std::string error;
+  bool success =
+      chromeos::LoginScreenExtensionUiHandler::Get(true /*can_create*/)
+          ->Show(extension(), options.url, user_can_close, &error);
+
+  if (!success)
+    return RespondNow(Error(error));
+  return RespondNow(NoArguments());
+}
+
+LoginScreenUiCloseFunction::LoginScreenUiCloseFunction() = default;
+LoginScreenUiCloseFunction::~LoginScreenUiCloseFunction() = default;
+
+ExtensionFunction::ResponseAction LoginScreenUiCloseFunction::Run() {
+  std::string error;
+  bool success =
+      chromeos::LoginScreenExtensionUiHandler::Get(true /*can_create*/)
+          ->Close(extension(), &error);
+
+  if (!success)
+    return RespondNow(Error(error));
+  return RespondNow(NoArguments());
+}
+
+}  // namespace extensions

chrome/browser/chromeos/extensions/login_screen_ui/login_screen_ui_api.h

+// Copyright 2019 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_CHROMEOS_EXTENSIONS_LOGIN_SCREEN_UI_LOGIN_SCREEN_UI_API_H_
+#define CHROME_BROWSER_CHROMEOS_EXTENSIONS_LOGIN_SCREEN_UI_LOGIN_SCREEN_UI_API_H_
+
+#include "extensions/browser/extension_function.h"
+
+namespace extensions {
+
+class LoginScreenUiShowFunction : public UIThreadExtensionFunction {
+ public:
+  LoginScreenUiShowFunction();
+
+  DECLARE_EXTENSION_FUNCTION("loginScreenUi.show", LOGINSCREENUI_SHOW)
+
+ protected:
+  ~LoginScreenUiShowFunction() override;
+
+  // ExtensionFunction:
+  ResponseAction Run() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(LoginScreenUiShowFunction);
+};
+
+class LoginScreenUiCloseFunction : public UIThreadExtensionFunction {
+ public:
+  LoginScreenUiCloseFunction();
+
+  DECLARE_EXTENSION_FUNCTION("loginScreenUi.close", LOGINSCREENUI_CLOSE)
+
+ protected:
+  ~LoginScreenUiCloseFunction() override;
+
+  // ExtensionFunction:
+  ResponseAction Run() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(LoginScreenUiCloseFunction);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_LOGIN_SCREEN_UI_LOGIN_SCREEN_UI_API_H_

chrome/common/extensions/api/_api_features.json

@@ -541,6 +541,10 @@
     "dependencies": ["permission:launcherSearchProvider"],
     "contexts": ["blessed_extension"]
   },
+  "loginScreenUi": {
+    "dependencies": ["permission:loginScreenUi"],
+    "contexts": ["blessed_extension"]
+  },
   "webcamPrivate": {
     "dependencies": ["permission:webcamPrivate"],
     "contexts": ["blessed_extension"]

chrome/common/extensions/api/_permission_features.json

@@ -435,6 +435,16 @@
                                                    // (staging)
     ]
   },
+  "loginScreenUi": {
+    "channel": "dev",
+    "extension_types": ["login_screen_extension"],
+    "location": "policy",
+    "platforms": ["chromeos"],
+    "whitelist": [
+      "7FE4A999359A456C4B0FB7B7AD85CEA29CA50519", // chrome.loginScreenUi test extension
+      "E219EE36A3B40612FD2A8CD6937B03EF0C97D3FE"  // Imprivata (login screen)
+    ]
+  },
   "webcamPrivate": {
     "channel": "stable",
     "extension_types": ["extension", "platform_app"],

chrome/common/extensions/api/api_sources.gni

@@ -97,6 +97,7 @@ if (is_chromeos) {
     "input_ime.json",
     "input_method_private.json",
     "launcher_search_provider.idl",
+    "login_screen_ui.idl",
     "platform_keys.idl",
     "platform_keys_internal.idl",
     "quick_unlock_private.idl",

chrome/common/extensions/api/login_screen_ui.idl

+// Copyright 2019 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.
+
+// Use the <code>chrome.loginScreenUi</code> API to show and hide custom
+// login UI.
+[platforms=("chromeos"),
+ implemented_in="chrome/browser/chromeos/extensions/login_screen_ui/login_screen_ui_api.h"]
+namespace loginScreenUi {
+
+  dictionary ShowOptions {
+    // Relative url of the contents to show.
+    DOMString url;
+
+    // Whether the user can close the window, defaults to false.
+    boolean? userCanClose;
+  };
+
+  // Callback that does not take arguments.
+  callback SimpleCallback = void ();
+
+  interface Functions {
+    // Opens a window, which is visible on top of the login and lock screen.
+    // |options|: Options for the custom login UI window.
+    static void show(ShowOptions options, optional SimpleCallback callback);
+
+    // Closes the login/lock screen UI window previously opened by this
+    // extension.
+    static void close(optional SimpleCallback callback);
+  };
+};

chrome/common/extensions/permissions/chrome_permission_message_rules.cc

@@ -654,6 +654,9 @@ ChromePermissionMessageRule::GetAllRules() {
       {IDS_EXTENSION_PROMPT_WARNING_ENTERPRISE_HARDWARE_PLATFORM,
        {APIPermission::kEnterpriseHardwarePlatform},
        {}},
+      {IDS_EXTENSION_PROMPT_WARNING_LOGIN_SCREEN_UI,
+       {APIPermission::kLoginScreenUi},
+       {}},
   };
 
   return std::vector<ChromePermissionMessageRule>(

extensions/browser/extension_function_histogram_value.h

@@ -1401,6 +1401,8 @@ enum HistogramValue {
   FILEMANAGERPRIVATE_SETARCSTORAGETOASTSHOWNFLAG = 1338,
   INPUTMETHODPRIVATE_SETCOMPOSITIONRANGE = 1339,
   BLUETOOTHPRIVATE_RECORDRECONNECTION = 1340,
+  LOGINSCREENUI_SHOW = 1341,
+  LOGINSCREENUI_CLOSE = 1342,
   // Last entry: Add new entries above, then run:
   // python tools/metrics/histograms/update_extension_histograms.py
   ENUM_BOUNDARY

extensions/browser/extension_protocols.cc

@@ -374,7 +374,7 @@ bool ExtensionCanLoadInIncognito(bool is_main_frame,
                                  bool extension_enabled_in_incognito) {
   if (!extension || !extension_enabled_in_incognito)
     return false;
-  if (!is_main_frame)
+  if (!is_main_frame || extension->is_login_screen_extension())
     return true;
 
   // Only allow incognito toplevel navigations to extension resources in

extensions/browser/extension_util.cc

@@ -44,6 +44,8 @@ bool IsIncognitoEnabled(const std::string& extension_id,
     // work in incognito mode.
     if (Manifest::IsComponentLocation(extension->location()))
       return true;
+    if (extension->is_login_screen_extension())
+      return true;
   }
   return ExtensionPrefs::Get(context)->IsIncognitoEnabled(extension_id);
 }

extensions/common/api/_api_features.json

@@ -423,8 +423,17 @@
   },
   "runtime": {
     "channel": "stable",
-    "extension_types": ["extension", "legacy_packaged_app", "platform_app"],
-    "contexts": ["blessed_extension", "lock_screen_extension", "extension_service_worker"]
+    "extension_types": [
+      "extension",
+      "legacy_packaged_app",
+      "platform_app",
+      "login_screen_extension"
+    ],
+    "contexts": [
+      "blessed_extension",
+      "lock_screen_extension",
+      "extension_service_worker"
+    ]
   },
   "runtime.getManifest": {
     "contexts": [

extensions/common/permissions/api_permission.h

@@ -258,6 +258,7 @@ class APIPermission {
     kSystemPowerSource = 214,
     kArcAppsPrivate = 215,
     kEnterpriseHardwarePlatform = 216,
+    kLoginScreenUi = 217,
     // Last entry: Add new entries above and ensure to update the
     // "ExtensionPermission3" enum in tools/metrics/histograms/histograms.xml
     // (by running update_extension_permission.py).

extensions/common/permissions/extensions_api_permissions.cc

@@ -78,6 +78,7 @@ constexpr APIPermissionInfo::InitInfo permissions_to_register[] = {
     {APIPermission::kLockScreen, "lockScreen"},
     {APIPermission::kLockWindowFullscreenPrivate, "lockWindowFullscreenPrivate",
      APIPermissionInfo::kFlagCannotBeOptional},
+    {APIPermission::kLoginScreenUi, "loginScreenUi"},
     {APIPermission::kMediaPerceptionPrivate, "mediaPerceptionPrivate"},
     {APIPermission::kMetricsPrivate, "metricsPrivate",
      APIPermissionInfo::kFlagCannotBeOptional},

tools/metrics/histograms/enums.xml

@@ -19491,6 +19491,8 @@ Called by update_net_error_codes.py.-->
   <int value="1338" label="FILEMANAGERPRIVATE_SETARCSTORAGETOASTSHOWNFLAG"/>
   <int value="1339" label="INPUTMETHODPRIVATE_SETCOMPOSITIONRANGE"/>
   <int value="1340" label="BLUETOOTHPRIVATE_RECORDRECONNECTION"/>
+  <int value="1341" label="LOGINSCREENUI_SHOW"/>
+  <int value="1342" label="LOGINSCREENUI_CLOSE"/>
 </enum>
 
 <enum name="ExtensionIconState">
@@ -20017,6 +20019,7 @@ Called by update_net_error_codes.py.-->
   <int value="214" label="kSystemPowerSource"/>
   <int value="215" label="kArcAppsPrivate"/>
   <int value="216" label="kEnterpriseHardwarePlatform"/>
+  <int value="217" label="kLoginScreenUi"/>
 </enum>
 
 <enum name="ExtensionServiceVerifyAllSuccess">