Add guest ui to the Help App.

This allows our client code (coming) to load in a sandboxed iframe.

Bug: 1012578, b/144121590
Change-Id: I0e3a1442a9d2959652a36737b8b22abd4d633de9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1904552
Commit-Queue: Rachel Carpenter <carpenterr@google.com>
Reviewed-by: Giovanni Ortuño Urquidi <ortuno@chromium.org>
Reviewed-by: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714727}

chromeos/components/help_app_ui/BUILD.gn

@@ -8,6 +8,8 @@ assert(is_chromeos, "Help App is Chrome OS only")
 
 static_library("help_app_ui") {
   sources = [
+    "help_app_guest_ui.cc",
+    "help_app_guest_ui.h",
     "help_app_ui.cc",
     "help_app_ui.h",
     "url_constants.cc",

chromeos/components/help_app_ui/help_app_guest_ui.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 "chromeos/components/help_app_ui/help_app_guest_ui.h"
+
+#include "chromeos/components/help_app_ui/url_constants.h"
+#include "chromeos/grit/chromeos_help_app_resources.h"
+#include "content/public/browser/web_ui_data_source.h"
+
+namespace chromeos {
+
+// static
+content::WebUIDataSource* CreateHelpAppGuestDataSource() {
+  content::WebUIDataSource* source =
+      content::WebUIDataSource::Create(kChromeUIHelpAppGuestHost);
+  source->AddResourcePath("app.html", IDR_HELP_APP_APP_HTML);
+  source->AddResourcePath("js/bootstrap.js", IDR_HELP_APP_BOOTSTRAP_JS);
+  // TODO(crbug.com/1023700): Better solution before launch.
+  source->DisableDenyXFrameOptions();
+  return source;
+}
+
+}  // namespace chromeos

chromeos/components/help_app_ui/help_app_guest_ui.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 CHROMEOS_COMPONENTS_HELP_APP_UI_HELP_APP_GUEST_UI_H_
+#define CHROMEOS_COMPONENTS_HELP_APP_UI_HELP_APP_GUEST_UI_H_
+
+namespace content {
+class WebUIDataSource;
+}
+
+namespace chromeos {
+// The data source creation for chrome://help-app-guest.
+content::WebUIDataSource* CreateHelpAppGuestDataSource();
+}  // namespace chromeos
+
+#endif  // CHROMEOS_COMPONENTS_HELP_APP_UI_HELP_APP_GUEST_UI_H_

chromeos/components/help_app_ui/help_app_ui.cc

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "chromeos/components/help_app_ui/help_app_ui.h"
+#include "chromeos/components/help_app_ui/help_app_guest_ui.h"
 
 #include "chromeos/components/help_app_ui/url_constants.h"
 #include "chromeos/grit/chromeos_help_app_resources.h"
@@ -13,7 +14,7 @@
 namespace chromeos {
 
 namespace {
-content::WebUIDataSource* CreateDataSource() {
+content::WebUIDataSource* CreateHostDataSource() {
   auto* source = content::WebUIDataSource::Create(kChromeUIHelpAppHost);
 
   // TODO(crbug.com/1012578): This is a placeholder only, update with the
@@ -27,8 +28,16 @@ content::WebUIDataSource* CreateDataSource() {
 }  // namespace
 
 HelpAppUI::HelpAppUI(content::WebUI* web_ui) : MojoWebUIController(web_ui) {
-  content::WebUIDataSource::Add(web_ui->GetWebContents()->GetBrowserContext(),
-                                CreateDataSource());
+  content::BrowserContext* browser_context =
+      web_ui->GetWebContents()->GetBrowserContext();
+  content::WebUIDataSource* host_source = CreateHostDataSource();
+  content::WebUIDataSource::Add(browser_context, host_source);
+  // We need a CSP override to use the guest origin in the host.
+  std::string csp = std::string("frame-src ") + kChromeUIHelpAppGuestURL + ";";
+  host_source->OverrideContentSecurityPolicyChildSrc(csp);
+
+  content::WebUIDataSource* guest_source = CreateHelpAppGuestDataSource();
+  content::WebUIDataSource::Add(browser_context, guest_source);
 }
 
 HelpAppUI::~HelpAppUI() = default;

chromeos/components/help_app_ui/resources/app.html

+<!-- 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. -->
+<!DOCTYPE html>
+<style>
+  body {
+    margin: 0;
+  }
+</style>
+<script src="/js/bootstrap.js"></script>
+<!-- TODO(crbug/1012578): Include scripts to run in the <iframe> sandbox that
+     communicate via postMessage to scripts running in index.html -->

chromeos/components/help_app_ui/resources/help_app_resources.grd

@@ -14,6 +14,8 @@
   <release seq="1">
     <includes>
       <!-- TODO(crbug.com/1012578): Add the run time resources .grdp here. -->
+      <include name="IDR_HELP_APP_APP_HTML" file="app.html"
+          type="BINDATA" />
       <include name="IDR_HELP_APP_INDEX_HTML" file="index.html"
           type="BINDATA" />
       <include name="IDR_HELP_APP_PWA_HTML" file="pwa.html" type="BINDATA" />
@@ -21,6 +23,9 @@
           type="BINDATA" />
       <include name="IDR_HELP_APP_ICON_192" file="app_icon_192.png"
           type="BINDATA" />
+      <include name="IDR_HELP_APP_BOOTSTRAP_JS"
+          file="js/bootstrap.js"
+          type="BINDATA" />
     </includes>
   </release>
 </grit>

chromeos/components/help_app_ui/resources/index.html

@@ -4,5 +4,21 @@
 <!DOCTYPE html>
 <meta charset="utf-8">
 <title>Help App</title>
+<style>
+  body {
+    height: 100vh;
+    margin: 0;
+    overflow: hidden;
+  }
+  /*
+   * This is the <iframe> style set for sandboxed guests that use
+   * guest_view_iframe_container.js.
+   */
+  iframe {
+    border: 0;
+    height: 100%;
+    width: 100%;
+  }
+</style>
 <script src="chrome://resources/mojo/mojo/public/js/mojo_bindings_lite.js"></script>
-<!-- TODO(crbug/1012578): Add sandboxed guest with content in an iframe. -->
+<iframe src="chrome://help-app-guest/app.html"></iframe>

chromeos/components/help_app_ui/resources/js/bootstrap.js

+// 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.
+
+// TODO(crbug/1012578): Pull in resources for app correctly.

chromeos/components/help_app_ui/test/help_app_ui_browsertest.js

@@ -9,6 +9,7 @@
 GEN('#include "chromeos/constants/chromeos_features.h"');
 
 const HOST_ORIGIN = 'chrome://help-app';
+const GUEST_ORIGIN = 'chrome://help-app-guest';
 
 var HelpAppUIBrowserTest = class extends testing.Test {
   /** @override */
@@ -29,5 +30,8 @@ var HelpAppUIBrowserTest = class extends testing.Test {
 
 // Tests that chrome://help-app goes somewhere instead of 404ing or crashing.
 TEST_F('HelpAppUIBrowserTest', 'HasChromeSchemeURL', () => {
+  const guest = document.querySelector('iframe');
+
   assertEquals(document.location.origin, HOST_ORIGIN);
+  assertEquals(guest.src, GUEST_ORIGIN + "/app.html");
 });

chromeos/components/help_app_ui/url_constants.cc

@@ -8,5 +8,7 @@ namespace chromeos {
 
 const char kChromeUIHelpAppHost[] = "help-app";
 const char kChromeUIHelpAppURL[] = "chrome://help-app/";
+const char kChromeUIHelpAppGuestHost[] = "help-app-guest";
+const char kChromeUIHelpAppGuestURL[] = "chrome://help-app-guest/";
 
 }  // namespace chromeos

chromeos/components/help_app_ui/url_constants.h

@@ -9,6 +9,8 @@ namespace chromeos {
 
 extern const char kChromeUIHelpAppHost[];
 extern const char kChromeUIHelpAppURL[];
+extern const char kChromeUIHelpAppGuestHost[];
+extern const char kChromeUIHelpAppGuestURL[];
 
 }  // namespace chromeos