Update the gestures notification to open the Help app.

At the moment it navigates to a support.google.com link in a tab. This
doesn't work offline, so utilising the help app which caches this
article instead.

Bug: b/157935237
Change-Id: Ibb5098b032bc959a826d52b1d05ebd7d14ab7cb3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2362166
Commit-Queue: Rachel Carpenter <carpenterr@chromium.org>
Reviewed-by: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800438}

chrome/browser/chromeos/web_applications/help_app_integration_browsertest.cc

@@ -13,6 +13,7 @@
 #include "chrome/browser/apps/app_service/app_service_proxy.h"
 #include "chrome/browser/apps/app_service/app_service_proxy_factory.h"
 #include "chrome/browser/chromeos/web_applications/system_web_app_integration_test.h"
+#include "chrome/browser/ui/ash/system_tray_client.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_window.h"
@@ -260,6 +261,30 @@ IN_PROC_BROWSER_TEST_P(HelpAppIntegrationTest, HelpAppV2ShowParentalControls) {
                               ->GetVisibleURL());
 }
 
+// Test that the Help App opens when Gesture help requested.
+IN_PROC_BROWSER_TEST_P(HelpAppIntegrationTest, HelpAppOpenGestures) {
+  WaitForTestSystemAppInstall();
+  base::HistogramTester histogram_tester;
+  const GURL expected_url("chrome://help-app/help/sub/3399710/id/9739838");
+  content::TestNavigationObserver navigation_observer(expected_url);
+  navigation_observer.StartWatchingNewWebContents();
+
+  SystemTrayClient::Get()->ShowGestureEducationHelp();
+  navigation_observer.Wait();
+
+  // There should be two browser windows, one regular and one for the help app.
+  EXPECT_EQ(2u, chrome::GetTotalBrowserCount());
+  // Help app should have opened at the gesture article.
+  EXPECT_EQ(expected_url, chrome::FindLastActive()
+                              ->tab_strip_model()
+                              ->GetActiveWebContents()
+                              ->GetVisibleURL());
+  // The HELP app is 18, see DefaultAppName in
+  // src/chrome/browser/apps/app_service/app_service_metrics.cc
+  histogram_tester.ExpectUniqueSample("Apps.DefaultAppLaunch.FromOtherApp", 18,
+                                      1);
+}
+
 INSTANTIATE_TEST_SUITE_P(
     All,
     HelpAppIntegrationTest,

chrome/browser/ui/ash/system_tray_client.cc

@@ -11,6 +11,8 @@
 #include "base/logging.h"
 #include "base/memory/weak_ptr.h"
 #include "base/metrics/user_metrics.h"
+#include "chrome/browser/apps/app_service/app_service_proxy.h"
+#include "chrome/browser/apps/app_service/app_service_proxy_factory.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_process_platform_part.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
@@ -20,6 +22,7 @@
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chrome/browser/chromeos/set_time_dialog.h"
 #include "chrome/browser/chromeos/system/system_clock.h"
+#include "chrome/browser/chromeos/web_applications/default_web_app_ids.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/lifetime/termination_notification.h"
 #include "chrome/browser/profiles/profile_manager.h"
@@ -284,11 +287,19 @@ void SystemTrayClient::ShowAccessibilitySettings() {
 }
 
 void SystemTrayClient::ShowGestureEducationHelp() {
-  chrome::ScopedTabbedBrowserDisplayer displayer(
-      ProfileManager::GetActiveUserProfile());
   base::RecordAction(base::UserMetricsAction("ShowGestureEducationHelp"));
-  ShowSingletonTab(displayer.browser(),
-                   GURL(chrome::kChromeOSGestureEducationHelpURL));
+  Profile* profile = ProfileManager::GetActiveUserProfile();
+  if (!profile)
+    return;
+
+  // Note that AppServiceProxy is null for off-the-record profiles. For more
+  // context, see https://crbug.com/1112197.
+  apps::AppServiceProxy* proxy = apps::AppServiceProxyFactory::GetForProfile(
+      profile->GetOriginalProfile());
+  proxy->LaunchAppWithUrl(
+      chromeos::default_web_apps::kHelpAppId, ui::EventFlags::EF_NONE,
+      GURL(chrome::kChromeOSGestureEducationHelpURL),
+      apps::mojom::LaunchSource::kFromOtherApp, display::kDefaultDisplayId);
 }
 
 void SystemTrayClient::ShowPaletteHelp() {

chrome/common/url_constants.cc

@@ -320,8 +320,11 @@ const char kChromeOSAssetPath[] = "/usr/share/chromeos-assets/";
 const char kChromeOSCreditsPath[] =
     "/opt/google/chrome/resources/about_os_credits.html";
 
+// TODO(carpenterr): Have a solution for plink mapping in Help App.
+// The magic numbers in this url are the topic and article ids currently
+// required to navigate directly to a help article in the Help App.
 const char kChromeOSGestureEducationHelpURL[] =
-    "https://support.google.com/chromebook?p=tablet_mode_gestures";
+    "chrome://help-app/help/sub/3399710/id/9739838";
 
 const char kChromePaletteHelpURL[] =
     "https://support.google.com/chromebook?p=stylus_help";