Reland "Add AR instrumentation test support"

This is a reland of a3015a89

Original change's description:
> Add AR instrumentation test support
>
> Adds the necessary changes to build and run
> AR (augmented reality) tests in Monochrome.
>
> Does not actually enable the test APK to be
> built or run anywhere - that will be added
> at a later time once additional work to
> properly run the tests on bots is done, e.g.
> installing the ArCore APK.
>
> Bug: 851020
> Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_layout_tests_slimming_paint_v2;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:linux_vr;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel;master.tryserver.blink:linux_trusty_blink_rel
> Change-Id: I4148fcc6626ef79852f78f6019cc7c6f297f3e37
> Reviewed-on: https://chromium-review.googlesource.com/1101958
> Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
> Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
> Reviewed-by: Brandon Jones <bajones@chromium.org>
> Reviewed-by: agrieve <agrieve@chromium.org>
> Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#573599}

TBR=yfriedman@chromium.org,mthiesse@chromium.org,bajones@chromium.org,agrieve@chromium.org

Bug: 851020
Change-Id: If8410366848ff25d276cb2473f773c153a32f94f
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_layout_tests_slimming_paint_v2;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:linux_vr;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel;master.tryserver.blink:linux_trusty_blink_rel
Reviewed-on: https://chromium-review.googlesource.com/1131715Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#573899}

build/config/android/rules.gni

@@ -2807,6 +2807,8 @@ if (enable_java_templates) {
         # Generate incremental apk related operations at runtime.
         public_deps += _incremental_apk_operations
       }
+    } else {
+      not_needed([ "_incremental_apk_operations" ])
     }
   }
 
@@ -2852,13 +2854,18 @@ if (enable_java_templates) {
   template("instrumentation_test_apk") {
     assert(defined(invoker.apk_name))
     testonly = true
+    _incremental_allowed =
+        !defined(invoker.never_incremental) || !invoker.never_incremental
     _apk_target_name = "${target_name}__apk"
     _test_runner_target_name = "${target_name}__test_runner_script"
     _dist_ijar_path =
         "$root_build_dir/test.lib.java/" + invoker.apk_name + ".jar"
-    _incremental_test_runner_target_name =
-        "${_test_runner_target_name}_incremental"
-    _incremental_test_name = "${invoker.target_name}_incremental"
+    if (_incremental_allowed) {
+      _incremental_test_runner_target_name =
+          "${_test_runner_target_name}_incremental"
+      _incremental_test_name = "${invoker.target_name}_incremental"
+    }
+
     if (incremental_apk_by_default) {
       _incremental_test_runner_target_name = _test_runner_target_name
       _incremental_test_name = invoker.target_name
@@ -2883,22 +2890,24 @@ if (enable_java_templates) {
         test_jar = _dist_ijar_path
       }
     }
-    test_runner_script(_incremental_test_runner_target_name) {
-      forward_variables_from(invoker,
-                             [
-                               "additional_apks",
-                               "apk_under_test",
-                               "data",
-                               "data_deps",
-                               "deps",
-                               "ignore_all_data_deps",
-                               "public_deps",
-                             ])
-      test_name = _incremental_test_name
-      test_type = "instrumentation"
-      apk_target = ":$_apk_target_name"
-      test_jar = _dist_ijar_path
-      incremental_install = true
+    if (_incremental_allowed) {
+      test_runner_script(_incremental_test_runner_target_name) {
+        forward_variables_from(invoker,
+                               [
+                                 "additional_apks",
+                                 "apk_under_test",
+                                 "data",
+                                 "data_deps",
+                                 "deps",
+                                 "ignore_all_data_deps",
+                                 "public_deps",
+                               ])
+        test_name = _incremental_test_name
+        test_type = "instrumentation"
+        apk_target = ":$_apk_target_name"
+        test_jar = _dist_ijar_path
+        incremental_install = true
+      }
     }
 
     android_apk(_apk_target_name) {
@@ -2981,14 +2990,16 @@ if (enable_java_templates) {
       }
     }
 
-    group("${target_name}_incremental") {
-      public_deps = [
-        ":$_incremental_test_runner_target_name",
-        ":${_apk_target_name}_dist_ijar",
-        ":${_apk_target_name}_incremental",
-      ]
-      if (defined(invoker.apk_under_test)) {
-        public_deps += [ "${invoker.apk_under_test}_incremental" ]
+    if (_incremental_allowed) {
+      group("${target_name}_incremental") {
+        public_deps = [
+          ":$_incremental_test_runner_target_name",
+          ":${_apk_target_name}_dist_ijar",
+          ":${_apk_target_name}_incremental",
+        ]
+        if (defined(invoker.apk_under_test)) {
+          public_deps += [ "${invoker.apk_under_test}_incremental" ]
+        }
       }
     }
   }

chrome/android/BUILD.gn

@@ -682,19 +682,45 @@ android_library("chrome_test_java") {
   ]
 }
 
-if (enable_vr) {
-  android_library("chrome_test_vr_java") {
+if (enable_vr || (enable_arcore && package_arcore)) {
+  # Desugaring doesn't seem to play nice with deps when there are multiple
+  # layers of android_library. If A is included in B's deps, and B is included
+  # in C's deps, desugar can fail to find classes from A. As a workaround,
+  # have each android_library have duplicate entries in their deps lists.
+  # See https://crbug.com/860018.
+  chrome_test_xr_java_deps = [
+    "//base:base_java",
+    "//base:base_java_test_support",
+    "//chrome/android:app_hooks_java",
+    "//chrome/android:chrome_java",
+    "//chrome/android:class_register_java",
+    "//chrome/test/android:chrome_java_test_support",
+    "//components/policy/android:policy_java",
+    "//content/public/android:content_java",
+    "//content/public/test/android:content_java_test_support",
+    "//net/android:net_java_test_support",
+    "//third_party/android_protobuf:protobuf_nano_javalib",
+    "//third_party/android_support_test_runner:rules_java",
+    "//third_party/android_support_test_runner:runner_java",
+    "//third_party/android_tools:android_arch_lifecycle_common_java",
+    "//third_party/android_tools:android_support_annotations_java",
+    "//third_party/android_tools:android_support_v7_appcompat_java",
+    "//third_party/android_tools:android_support_v7_recyclerview_java",
+    "//third_party/custom_tabs_client:custom_tabs_support_java",
+    "//third_party/junit",
+    "//third_party/ub-uiautomator:ub_uiautomator_java",
+    "//ui/android:ui_java",
+  ]
+
+  # Files used for both VR and AR testing
+  android_library("chrome_test_xr_java") {
     testonly = true
 
     java_files = [
       "javatests/src/org/chromium/chrome/browser/customtabs/CustomTabActivityTestRule.java",
       "javatests/src/org/chromium/chrome/browser/customtabs/CustomTabsTestUtils.java",
       "javatests/src/org/chromium/chrome/browser/media/RouterTestUtils.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/EmulatedVrController.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/mock/MockBrowserKeyboardInterface.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/mock/MockVrCoreVersionCheckerImpl.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/mock/MockVrDaydreamApi.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/nfc_apk/SimNfcActivity.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/rules/ChromeTabbedActivityVrTestRule.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/rules/CustomTabActivityVrTestRule.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/rules/HeadTrackingMode.java",
@@ -703,68 +729,79 @@ if (enable_vr) {
       "javatests/src/org/chromium/chrome/browser/vr_shell/rules/VrTestRule.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/rules/WebappActivityVrTestRule.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/util/HeadTrackingUtils.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/util/NativeUiUtils.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/util/NfcSimUtils.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/util/TransitionUtils.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/util/VrInfoBarUtils.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/util/VrShellDelegateUtils.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/util/VrTestRuleUtils.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/util/VrTransitionUtils.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/util/XrTransitionUtils.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/TestFramework.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/TestVrShellDelegate.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/VrFeedbackInfoBarTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/VrInstallUpdateInfoBarTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellCompositorViewHolderTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellControllerInputTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellDialogTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellNativeUiTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellNavigationTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTransitionTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellWebInputEditingTest.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/VrTestFramework.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/WebVrDeviceTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/WebVrInputTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/WebVrTabTest.java",
-      "javatests/src/org/chromium/chrome/browser/vr_shell/WebVrTransitionTest.java",
       "javatests/src/org/chromium/chrome/browser/vr_shell/XrTestFramework.java",
       "javatests/src/org/chromium/chrome/browser/webapps/TestFetchStorageCallback.java",
       "javatests/src/org/chromium/chrome/browser/webapps/WebappActivityTestRule.java",
     ]
 
-    deps = [
-      "//base:base_java",
-      "//base:base_java_test_support",
-      "//chrome/android:app_hooks_java",
-      "//chrome/android:chrome_java",
-      "//chrome/android:class_register_java",
-      "//chrome/test/android:chrome_java_test_support",
-      "//components/policy/android:policy_java",
-      "//content/public/android:content_java",
-      "//content/public/test/android:content_java_test_support",
-      "//net/android:net_java_test_support",
-      "//third_party/android_protobuf:protobuf_nano_javalib",
-      "//third_party/android_support_test_runner:rules_java",
-      "//third_party/android_support_test_runner:runner_java",
-      "//third_party/android_tools:android_arch_lifecycle_common_java",
-      "//third_party/android_tools:android_support_annotations_java",
-      "//third_party/android_tools:android_support_v7_appcompat_java",
-      "//third_party/android_tools:android_support_v7_recyclerview_java",
-      "//third_party/custom_tabs_client:custom_tabs_support_java",
-      "//third_party/gvr-android-sdk:controller_test_api_java",
-      "//third_party/gvr-android-sdk:gvr_common_java",
-      "//third_party/junit",
-      "//third_party/ub-uiautomator:ub_uiautomator_java",
-      "//ui/android:ui_java",
-    ]
+    deps = chrome_test_xr_java_deps
 
     data = [
-      "//chrome/android/shared_preference_files/test/",
       "//chrome/test/data/vr/e2e_test_files/",
-      "//third_party/gvr-android-sdk/test-apks/",
       "//third_party/WebKit/LayoutTests/resources/testharness.js",
     ]
   }
+
+  if (enable_vr) {
+    # All files necessary for VR instrumentation tests
+    android_library("chrome_test_vr_java") {
+      testonly = true
+
+      java_files = [
+        "javatests/src/org/chromium/chrome/browser/vr_shell/EmulatedVrController.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/mock/MockBrowserKeyboardInterface.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/mock/MockVrDaydreamApi.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/nfc_apk/SimNfcActivity.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/util/NativeUiUtils.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/util/NfcSimUtils.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/util/VrInfoBarUtils.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/VrFeedbackInfoBarTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/VrInstallUpdateInfoBarTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellCompositorViewHolderTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellControllerInputTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellDialogTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellNativeUiTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellNavigationTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTransitionTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/VrShellWebInputEditingTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/WebVrDeviceTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/WebVrInputTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/WebVrTabTest.java",
+        "javatests/src/org/chromium/chrome/browser/vr_shell/WebVrTransitionTest.java",
+      ]
+
+      deps = chrome_test_xr_java_deps + [
+               "//chrome/android:chrome_test_xr_java",
+               "//third_party/gvr-android-sdk:controller_test_api_java",
+               "//third_party/gvr-android-sdk:gvr_common_java",
+             ]
+
+      data = [
+        "//chrome/android/shared_preference_files/test/",
+        "//third_party/gvr-android-sdk/test-apks/",
+      ]
+    }
+  }
+
+  if (enable_arcore && package_arcore) {
+    # All files necessary for AR instrumentation tests
+    android_library("chrome_test_ar_java") {
+      testonly = true
+
+      java_files = [ "javatests/src/org/chromium/chrome/browser/vr_shell/WebXrArSessionTest.java" ]
+
+      deps =
+          chrome_test_xr_java_deps + [ "//chrome/android:chrome_test_xr_java" ]
+    }
+  }
 }
 
 # Overrides icon / name defined in chrome_java_resources.
@@ -1290,6 +1327,8 @@ chrome_public_test_vr_apk_manifest =
     "$root_gen_dir/chrome_public_test_vr_apk_manifest/AndroidManifest.xml"
 chrome_sync_shell_test_apk_manifest =
     "$root_gen_dir/chrome_sync_shell_test_apk_manifest/AndroidManifest.xml"
+monochrome_public_test_ar_apk_manifest =
+    "$root_gen_dir/monochrome_public_test_ar_apk_manifest/AndroidManifest.xml"
 vr_nfc_simulator_apk_manifest =
     "$root_gen_dir/vr_nfc_simulator_apk_manifest/AndroidManifest.xml"
 
@@ -1297,12 +1336,28 @@ jinja_template("chrome_public_test_apk_manifest") {
   input = "javatests/AndroidManifest.xml"
   output = chrome_public_test_apk_manifest
   variables = chrome_public_jinja_variables
+  variables += [
+    "min_sdk_version=16",
+    "target_sdk_version=$android_sdk_version",
+  ]
 }
 
 jinja_template("chrome_public_test_vr_apk_manifest") {
   input = "javatests/AndroidManifest.xml"
   output = chrome_public_test_vr_apk_manifest
   variables = chrome_public_jinja_variables
+  variables += [
+    "min_sdk_version=16",
+    "target_sdk_version=$android_sdk_version",
+  ]
+}
+
+jinja_template("monochrome_public_test_ar_apk_manifest") {
+  input = "javatests/AndroidManifest_monochrome.xml"
+  output = monochrome_public_test_ar_apk_manifest
+  variables = chrome_public_jinja_variables +
+              monochrome_android_manifest_jinja_variables +
+              [ "target_sdk_version=$android_sdk_version" ]
 }
 
 jinja_template("vr_nfc_simulator_apk_manifest") {
@@ -1385,6 +1440,35 @@ if (enable_vr) {
   }
 }
 
+if (enable_arcore && package_arcore) {
+  instrumentation_test_apk("monochrome_public_test_ar_apk") {
+    apk_name = "MonochromePublicTestAr"
+    apk_under_test = ":monochrome_public_apk"
+    android_manifest = monochrome_public_test_ar_apk_manifest
+    android_manifest_dep = ":monochrome_public_test_ar_apk_manifest"
+
+    deps = [
+      ":chrome_test_ar_java",
+      "//third_party/android_tools:android_test_mock_java",
+    ]
+    additional_apks = [ "//net/android:net_test_support_apk" ]
+    proguard_enabled = !is_java_debug
+    if (proguard_enabled && !enable_proguard_obfuscation) {
+      proguard_configs = [ "//base/android/proguard/enable_obfuscation.flags" ]
+      proguard_config_exclusions =
+          [ "//base/android/proguard/disable_chromium_obfuscation.flags" ]
+    }
+    alternative_android_sdk_dep = webview_framework_dep
+
+    # The test APK contains code from both the APK under test and the
+    # test APK when proguard is enabled. That causes this APK to exceed
+    # the dex limit.
+    enable_multidex = proguard_enabled
+
+    never_incremental = true
+  }
+}
+
 instrumentation_test_apk("chrome_sync_shell_test_apk") {
   apk_name = "ChromeSyncShellTest"
   apk_under_test = ":chrome_sync_shell_apk"

chrome/android/javatests/AndroidManifest.xml

@@ -7,7 +7,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="org.chromium.chrome.tests">
 
-    <uses-sdk android:minSdkVersion="16" android:targetSdkVersion="23" />
+    <uses-sdk android:minSdkVersion="{{min_sdk_version}}" android:targetSdkVersion="{{target_sdk_version}}" />
     <uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" />
     <uses-permission android:name="android.permission.READ_LOGS"/>
     <uses-permission android:name="android.permission.WAKE_LOCK" />
@@ -15,7 +15,7 @@
     <uses-permission android:name="android.permission.INTERNET" />
 
     <application
-        android:label="ChromePublicTest">
+        android:label="{% block application_name %}ChromePublicTest{% endblock %}">
 
         <uses-library android:name="android.test.runner" />
 

chrome/android/javatests/AndroidManifest_monochrome.xml

+{% extends "chrome/android/javatests/AndroidManifest.xml" %}
+
+## Copyright 2018 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.
+
+## Note: This is a jinja2 template, processed at build time into the final manifest.
+##
+
+{% block application_name %}MonochromePublicTest{% endblock %}
\ No newline at end of file

chrome/android/javatests/src/org/chromium/chrome/browser/media/remote/CastTestRule.java

@@ -178,6 +178,7 @@ public class CastTestRule extends ChromeActivityTestRule<ChromeActivity> {
         return waitForStates(states, waitTimeMs);
     }
 
+    @Override
     public EmbeddedTestServer getTestServer() {
         return mTestServer;
     }

chrome/android/javatests/src/org/chromium/chrome/browser/notifications/NotificationTestRule.java

@@ -61,6 +61,7 @@ public class NotificationTestRule extends ChromeActivityTestRule<ChromeTabbedAct
     }
 
     /** Returns the test server. */
+    @Override
     public EmbeddedTestServer getTestServer() {
         return mTestServer;
     }

chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/TestFramework.java

@@ -209,6 +209,18 @@ public class TestFramework {
         }
     }
 
+    /**
+     * Helper function to make sure that the JavaScript test harness did not detect any failures.
+     * Similar to endTest, but does not fail if the test is still detected as running. This is
+     * useful because not all tests make use of the test harness' test/assert features (particularly
+     * simple enter/exit tests), but may still want to ensure that no unexpected JavaScript errors
+     * were encountered.
+     * @param webContents The Webcontents for the tab to check for failures in.
+     */
+    public static void assertNoJavaScriptErrors(WebContents webContents) {
+        Assert.assertNotEquals(checkTestStatus(webContents), STATUS_FAILED);
+    }
+
     /**
      * Polls the provided JavaScript boolean until the timeout is reached or
      * the boolean is true.

chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/WebXrArSessionTest.java

+// Copyright 2018 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.
+
+package org.chromium.chrome.browser.vr_shell;
+
+import static org.chromium.chrome.browser.vr_shell.TestFramework.PAGE_LOAD_TIMEOUT_S;
+import static org.chromium.chrome.browser.vr_shell.XrTestFramework.POLL_TIMEOUT_LONG_MS;
+
+import android.os.Build;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.filters.MediumTest;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.RuleChain;
+import org.junit.runner.RunWith;
+
+import org.chromium.base.test.params.ParameterAnnotations.ClassParameter;
+import org.chromium.base.test.params.ParameterAnnotations.UseRunnerDelegate;
+import org.chromium.base.test.params.ParameterSet;
+import org.chromium.base.test.params.ParameterizedRunner;
+import org.chromium.base.test.util.CommandLineFlags;
+import org.chromium.base.test.util.MinAndroidSdkLevel;
+import org.chromium.chrome.browser.ChromeSwitches;
+import org.chromium.chrome.browser.vr_shell.rules.VrActivityRestriction;
+import org.chromium.chrome.browser.vr_shell.util.VrTestRuleUtils;
+import org.chromium.chrome.browser.vr_shell.util.XrTransitionUtils;
+import org.chromium.chrome.test.ChromeActivityTestRule;
+import org.chromium.chrome.test.ChromeJUnit4RunnerDelegate;
+import org.chromium.net.test.EmbeddedTestServer;
+
+import java.util.List;
+import java.util.concurrent.Callable;
+
+/**
+ * End-to-end tests for testing WebXR for AR's requestSession behavior.
+ */
+@RunWith(ParameterizedRunner.class)
+@UseRunnerDelegate(ChromeJUnit4RunnerDelegate.class)
+@CommandLineFlags.
+Add({ChromeSwitches.DISABLE_FIRST_RUN_EXPERIENCE, "enable-features=WebXR,WebXRHitTest"})
+@MinAndroidSdkLevel(Build.VERSION_CODES.N) // WebXR for AR is only supported on N+
+public class WebXrArSessionTest {
+    @ClassParameter
+    private static List<ParameterSet> sClassParams =
+            VrTestRuleUtils.generateDefaultVrTestRuleParameters();
+    @Rule
+    public RuleChain mRuleChain;
+
+    private ChromeActivityTestRule mTestRule;
+    private XrTestFramework mXrTestFramework;
+    private EmbeddedTestServer mServer;
+
+    private boolean mShouldCreateServer;
+
+    public WebXrArSessionTest(Callable<ChromeActivityTestRule> callable) throws Exception {
+        mTestRule = callable.call();
+        mRuleChain = VrTestRuleUtils.wrapRuleInVrActivityRestrictionRule(mTestRule);
+    }
+
+    @Before
+    public void setUp() throws Exception {
+        mXrTestFramework = new XrTestFramework(mTestRule);
+        // WebappActivityTestRule automatically creates a test server, and creating multiple causes
+        // it to crash hitting a DCHECK. So, only handle the server ourselves if whatever test rule
+        // we're using doesn't create one itself.
+        mServer = mTestRule.getTestServer();
+        if (mServer == null) {
+            mShouldCreateServer = true;
+            mServer = EmbeddedTestServer.createAndStartServer(InstrumentationRegistry.getContext());
+        }
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        if (mServer != null && mShouldCreateServer) {
+            mServer.stopAndDestroyServer();
+        }
+    }
+
+    /**
+     * Tests that a session request for AR succeeds.
+     */
+    @Test
+    @MediumTest
+    @VrActivityRestriction({VrActivityRestriction.SupportedActivity.ALL})
+    public void testArRequestSessionSucceeds() throws InterruptedException {
+        mXrTestFramework.loadUrlAndAwaitInitialization(
+                mServer.getURL(XrTestFramework.getEmbeddedServerPathForHtmlTestFile(
+                        "test_ar_request_session_succeeds")),
+                PAGE_LOAD_TIMEOUT_S);
+        XrTransitionUtils.enterArSessionOrFail(mXrTestFramework.getFirstTabWebContents());
+        XrTestFramework.assertNoJavaScriptErrors(mXrTestFramework.getFirstTabWebContents());
+    }
+
+    /**
+     * Tests that repeatedly starting and stopping AR sessions does not cause any unexpected
+     * behavior. Regression test for https://crbug.com/837894.
+     */
+    @Test
+    @MediumTest
+    @VrActivityRestriction({VrActivityRestriction.SupportedActivity.ALL})
+    public void testRepeatedArSessionsSucceed() throws InterruptedException {
+        mXrTestFramework.loadUrlAndAwaitInitialization(
+                mServer.getURL(XrTestFramework.getEmbeddedServerPathForHtmlTestFile(
+                        "test_ar_request_session_succeeds")),
+                PAGE_LOAD_TIMEOUT_S);
+        for (int i = 0; i < 2; i++) {
+            XrTransitionUtils.enterArSessionOrFail(mXrTestFramework.getFirstTabWebContents());
+            XrTransitionUtils.endArSession(mXrTestFramework.getFirstTabWebContents());
+        }
+        XrTestFramework.assertNoJavaScriptErrors(mXrTestFramework.getFirstTabWebContents());
+    }
+
+    /**
+     * Tests that repeated calls to requestSession on the same page only prompts the user for
+     * camera permissions once.
+     */
+    @Test
+    @MediumTest
+    @VrActivityRestriction({VrActivityRestriction.SupportedActivity.ALL})
+    public void testRepeatedArSessionsOnlyPromptPermissionsOnce() throws InterruptedException {
+        mXrTestFramework.loadUrlAndAwaitInitialization(
+                mServer.getURL(XrTestFramework.getEmbeddedServerPathForHtmlTestFile(
+                        "test_ar_request_session_succeeds")),
+                PAGE_LOAD_TIMEOUT_S);
+        Assert.assertTrue(XrTransitionUtils.arSessionRequestWouldTriggerPermissionPrompt(
+                mXrTestFramework.getFirstTabWebContents()));
+        XrTransitionUtils.enterArSessionOrFail(mXrTestFramework.getFirstTabWebContents());
+        XrTransitionUtils.endArSession(mXrTestFramework.getFirstTabWebContents());
+        // Manually run through the same steps as enterArSessionOrFail so that we don't trigger
+        // its automatic permission acceptance.
+        Assert.assertFalse(XrTransitionUtils.arSessionRequestWouldTriggerPermissionPrompt(
+                mXrTestFramework.getFirstTabWebContents()));
+        XrTransitionUtils.enterPresentation(mXrTestFramework.getFirstTabWebContents());
+        Assert.assertTrue(XrTestFramework.pollJavaScriptBoolean(
+                "sessionInfos[sessionTypes.AR].currentSession != null", POLL_TIMEOUT_LONG_MS,
+                mXrTestFramework.getFirstTabWebContents()));
+    }
+}
\ No newline at end of file

chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/util/TransitionUtils.java

@@ -121,7 +121,6 @@ public class TransitionUtils {
      * JavaScript step to finish.
      *
      * Only meant to be used alongside the test framework from VrTestFramework.
-     * @param cvc The ContentViewCore for the tab the canvas is in.
      * @param webContents The WebContents for the tab the JavaScript step is in.
      */
     public static void enterPresentationAndWait(WebContents webContents) {

chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/util/XrTransitionUtils.java

@@ -5,20 +5,23 @@
 package org.chromium.chrome.browser.vr_shell.util;
 
 import static org.chromium.chrome.browser.vr_shell.XrTestFramework.POLL_TIMEOUT_LONG_MS;
+import static org.chromium.chrome.browser.vr_shell.XrTestFramework.POLL_TIMEOUT_SHORT_MS;
+
+import android.content.DialogInterface;
 
 import org.junit.Assert;
 
+import org.chromium.base.ThreadUtils;
+import org.chromium.chrome.browser.permissions.PermissionDialogController;
 import org.chromium.chrome.browser.vr_shell.TestVrShellDelegate;
 import org.chromium.chrome.browser.vr_shell.XrTestFramework;
+import org.chromium.content.browser.test.util.Criteria;
+import org.chromium.content.browser.test.util.CriteriaHelper;
 import org.chromium.content_public.browser.WebContents;
 
 /**
  * Class containing utility functions for transitioning between different
- * states in VR, such as fullscreen, WebVR presentation, and the VR browser.
- *
- * All the transitions in this class are performed directly through Chrome,
- * as opposed to NFC tag simulation which involves receiving an intent from
- * an outside application (VR Services).
+ * states in WebXR, e.g. entering exclusive or AR sessions.
  */
 public class XrTransitionUtils extends TransitionUtils {
     /**
@@ -26,9 +29,72 @@ public class XrTransitionUtils extends TransitionUtils {
      * the two APIs.
      */
     public static void enterPresentationOrFail(WebContents webContents) {
+        XrTestFramework.runJavaScriptOrFail(
+                "sessionTypeToRequest = sessionTypes.EXCLUSIVE", POLL_TIMEOUT_LONG_MS, webContents);
         enterPresentation(webContents);
         Assert.assertTrue(XrTestFramework.pollJavaScriptBoolean(
-                "exclusiveSession != null", POLL_TIMEOUT_LONG_MS, webContents));
+                "sessionInfos[sessionTypes.EXCLUSIVE].currentSession != null", POLL_TIMEOUT_LONG_MS,
+                webContents));
         Assert.assertTrue(TestVrShellDelegate.getVrShellForTesting().getWebVrModeEnabled());
     }
+
+    /**
+     * Requests that WebXR start an AR session, failing the test if it does not succeed.
+     * @param webContents The WebContents to run start the AR session in.
+     */
+    public static void enterArSessionOrFail(WebContents webContents) {
+        XrTestFramework.runJavaScriptOrFail(
+                "sessionTypeToRequest = sessionTypes.AR", POLL_TIMEOUT_LONG_MS, webContents);
+        // Requesting an AR session for the first time on a page will always prompt for camera
+        // permissions, but not on subsequent requests, so check to see if we'll need to accept it
+        // after requesting the session.
+        boolean expectPermissionPrompt = arSessionRequestWouldTriggerPermissionPrompt(webContents);
+        // TODO(bsheedy): Rename enterPresentation since it's used for both presentation and AR?
+        enterPresentation(webContents);
+        if (expectPermissionPrompt) {
+            // Wait for the permission prompt to appear.
+            CriteriaHelper.pollUiThread(new Criteria() {
+                @Override
+                public boolean isSatisfied() {
+                    return PermissionDialogController.getInstance().getCurrentDialogForTesting()
+                            != null;
+                }
+            });
+            // Accept the permission prompt.
+            ThreadUtils.runOnUiThreadBlocking(() -> {
+                PermissionDialogController.getInstance()
+                        .getCurrentDialogForTesting()
+                        .getButton(DialogInterface.BUTTON_POSITIVE)
+                        .performClick();
+            });
+        }
+        Assert.assertTrue(XrTestFramework.pollJavaScriptBoolean(
+                "sessionInfos[sessionTypes.AR].currentSession != null", POLL_TIMEOUT_LONG_MS,
+                webContents));
+    }
+
+    /**
+     * Ends the current AR session.
+     * @param webContents The WebContents to end the AR session in.
+     */
+    public static void endArSession(WebContents webContents) {
+        XrTestFramework.runJavaScriptOrFail("sessionInfos[sessionTypes.AR].currentSession.end()",
+                POLL_TIMEOUT_SHORT_MS, webContents);
+    }
+
+    /**
+     * Checks whether an AR session request would trigger a Camera permission prompt.
+     * @param webContents The WebContents to check permissions in.
+     * @return True if an AR session request will cause a permission prompt, false otherwise.
+     */
+    public static boolean arSessionRequestWouldTriggerPermissionPrompt(WebContents webContents) {
+        XrTestFramework.runJavaScriptOrFail("checkIfArSessionWouldTriggerPermissionPrompt()",
+                POLL_TIMEOUT_SHORT_MS, webContents);
+        Assert.assertTrue(XrTestFramework.pollJavaScriptBoolean(
+                "arSessionRequestWouldTriggerPermissionPrompt !== null", POLL_TIMEOUT_SHORT_MS,
+                webContents));
+        return Boolean.valueOf(
+                XrTestFramework.runJavaScriptOrFail("arSessionRequestWouldTriggerPermissionPrompt",
+                        POLL_TIMEOUT_SHORT_MS, webContents));
+    }
 }

chrome/android/javatests/src/org/chromium/chrome/browser/webapps/WebappActivityTestRule.java

@@ -80,6 +80,7 @@ public class WebappActivityTestRule extends ChromeActivityTestRule<WebappActivit
         super(WebappActivity0.class);
     }
 
+    @Override
     public EmbeddedTestServer getTestServer() {
         return mTestServerRule.getServer();
     }

chrome/browser/vr/test/xr_browser_test.cc

@@ -24,19 +24,23 @@ void XrBrowserTestBase::EnterPresentation(content::WebContents* web_contents) {
 void XrBrowserTestBase::EnterPresentationOrFail(
     content::WebContents* web_contents) {
   EnterPresentation(web_contents);
-  EXPECT_TRUE(PollJavaScriptBoolean("exclusiveSession!= null", kPollTimeoutLong,
-                                    web_contents));
+  EXPECT_TRUE(PollJavaScriptBoolean(
+      "sessionInfos[sessionTypes.EXCLUSIVE].currentSession != null",
+      kPollTimeoutLong, web_contents));
 }
 
 void XrBrowserTestBase::ExitPresentation(content::WebContents* web_contents) {
-  EXPECT_TRUE(content::ExecuteScript(web_contents, "exclusiveSession.end()"));
+  EXPECT_TRUE(content::ExecuteScript(
+      web_contents,
+      "sessionInfos[sessionTypes.EXCLUSIVE].currentSession.end()"));
 }
 
 void XrBrowserTestBase::ExitPresentationOrFail(
     content::WebContents* web_contents) {
   ExitPresentation(web_contents);
-  EXPECT_TRUE(PollJavaScriptBoolean("exclusiveSession == null",
-                                    kPollTimeoutLong, web_contents));
+  EXPECT_TRUE(PollJavaScriptBoolean(
+      "sessionInfos[sessionTypes.EXCLUSIVE].currentSession == null",
+      kPollTimeoutLong, web_contents));
 }
 
 }  // namespace vr

chrome/test/android/javatests/src/org/chromium/chrome/test/ChromeActivityTestRule.java

@@ -56,6 +56,7 @@ import org.chromium.content.browser.test.util.JavaScriptUtils;
 import org.chromium.content.browser.test.util.RenderProcessLimit;
 import org.chromium.content_public.browser.LoadUrlParams;
 import org.chromium.content_public.browser.WebContents;
+import org.chromium.net.test.EmbeddedTestServer;
 import org.chromium.ui.base.PageTransition;
 
 import java.lang.reflect.AnnotatedElement;
@@ -621,6 +622,13 @@ public class ChromeActivityTestRule<T extends ChromeActivity> extends ActivityTe
         return mCurrentTestName;
     }
 
+    /**
+     * Gets the ChromeActivityTestRule's EmbeddedTestServer instance if it has one.
+     */
+    public EmbeddedTestServer getTestServer() {
+        return null;
+    }
+
     /**
      * @return {@link WebContents} of the active tab of the activity.
      */

chrome/test/data/vr/e2e_test_files/html/test_ar_request_session_succeeds.html

+<!doctype html>
+<!--
+Tests that AR requestSessions succeed.
+-->
+<html>
+  <head>
+    <link rel="stylesheet" type="text/css" href="../resources/webxr_e2e.css">
+  </head>
+  <body>
+    <canvas id="webgl-canvas"></canvas>
+    <script src="../../../../../../third_party/WebKit/LayoutTests/resources/testharness.js"></script>
+    <script src="../resources/webxr_e2e.js"></script>
+    <script>var shouldAutoCreateNonExclusiveSession = false;</script>
+    <script src="../resources/webxr_boilerplate.js"></script>
+  </body>
+</html>

chrome/test/data/vr/e2e_test_files/html/test_non_exclusive_stops_during_exclusive.html

@@ -21,7 +21,7 @@ is active, but resumes afterwards.
           // Verify that we call a rAF once, then make sure any subsequent calls
           // are not done while there is an exclusive session.
           onMagicWindowXRFrameCallback = function() {
-            if (exclusiveSession !== null) {
+            if (sessionInfos[sessionTypes.EXCLUSIVE].currentSession !== null) {
               t.step( () => {
                 assert_unreached(
                     "Non-exclusive rAF called during exclusive session");

chrome/test/data/vr/e2e_test_files/html/test_webxr_input.html

@@ -62,9 +62,10 @@ that Daydream controller input is registered when using Daydream View.
 
       function stepSetupListeners(numIterations) {
         iterations = numIterations;
-        exclusiveSession.addEventListener('selectstart', onSelectStart, false);
-        exclusiveSession.addEventListener('selectend', onSelectEnd, false);
-        exclusiveSession.addEventListener('select', onSelect, false);
+        let currentSession = sessionInfos[sessionTypes.EXCLUSIVE].currentSession;
+        currentSession.addEventListener('selectstart', onSelectStart, false);
+        currentSession.addEventListener('selectend', onSelectEnd, false);
+        currentSession.addEventListener('select', onSelect, false);
       }
     </script>
   </body>

chrome/test/data/vr/e2e_test_files/html/test_webxr_poses.html

@@ -18,6 +18,9 @@ test can query for whether each submitted frame used the correct pose.
       var t = async_test("Pose data is correct");
       var frame_id = 0;
       var frame_data_array = {};
+      // We exit presentation before checking stuff that needs the frame of
+      // reference, so we need to cache its value.
+      var cached_frame_of_ref = null;
 
       function FloatCompare(a, b) {
         return Math.abs(a-b) < 0.001;
@@ -40,13 +43,13 @@ test can query for whether each submitted frame used the correct pose.
 
       function checkFrameView(frame_id, eye, expected) {
         let frame_data = frame_data_array[frame_id];
-        let pose = frame_data.getDevicePose(exclusiveFrameOfRef);
+        let pose = frame_data.getDevicePose(cached_frame_of_ref);
         return MatrixCompare(pose.getViewMatrix(frame_data_array[frame_id].views[eye]), expected);
       }
 
       function checkFramePose(frame_id, expected) {
         let frame_data = frame_data_array[frame_id];
-        let pose = frame_data.getDevicePose(exclusiveFrameOfRef);
+        let pose = frame_data.getDevicePose(cached_frame_of_ref);
         if (!pose) {
           // We can intermittently get null poses.  For now treat them as passing,
           // even though this should be fixed.
@@ -63,6 +66,7 @@ test can query for whether each submitted frame used the correct pose.
         // Encode an index into the clear color.
         frame_id++;
         frame_data_array[frame_id] = frame;
+        cached_frame_of_ref = sessionInfos[sessionTypes.EXCLUSIVE].currentFrameOfRef;
 
         var encoded_frame_id = {};
         encoded_frame_id.r = frame_id % 256;

chrome/test/data/vr/e2e_test_files/html/webxr_test_pose_data_unfocused_tab.html

@@ -27,7 +27,7 @@ Tests that WebXR doesn't update frame data when the tab is not focused
             return;
           }
           onMagicWindowXRFrameCallback = null;
-          pose = frame.getDevicePose(magicWindowFrameOfRef);
+          pose = frame.getDevicePose(sessionInfos[sessionTypes.MAGIC_WINDOW].currentFrameOfRef);
           t.step( () => {
             assert_true(pose != null,
                 "getDevicePose returned a non-null object");

chrome/test/data/vr/e2e_test_files/resources/webxr_boilerplate.js

@@ -22,17 +22,81 @@ var onMagicWindowXRFrameCallback = null;
 var onExclusiveXRFrameCallback = null;
 var shouldSubmitFrame = true;
 var hasPresentedFrame = false;
+var arSessionRequestWouldTriggerPermissionPrompt = null;
 
-var magicWindowSession = null;
-var magicWindowFrameOfRef = null;
-var exclusiveSession = null;
-var exclusiveFrameOfRef = null;
+var sessionTypes = Object.freeze({
+  EXCLUSIVE: 1,
+  AR: 2,
+  MAGIC_WINDOW: 3
+});
+var sessionTypeToRequest = sessionTypes.EXCLUSIVE;
+
+class SessionInfo {
+  constructor() {
+    this.session = null;
+    this.frameOfRef = null;
+  }
+
+  get currentSession() {
+    return this.session;
+  }
+
+  get currentFrameOfRef() {
+    return this.frameOfRef;
+  }
+
+  set currentSession(session) {
+    this.session = session;
+  }
+
+  set currentFrameOfRef(frameOfRef) {
+    this.frameOfRef = frameOfRef;
+  }
+
+  clearSession() {
+    this.session = null;
+    this.frameOfRef = null;
+  }
+}
+
+var sessionInfos = {}
+sessionInfos[sessionTypes.EXCLUSIVE] = new SessionInfo();
+sessionInfos[sessionTypes.AR] = new SessionInfo();
+sessionInfos[sessionTypes.MAGIC_WINDOW] = new SessionInfo();
+
+function getSessionType(session) {
+  if (session.exclusive) {
+    return sessionTypes.EXCLUSIVE;
+  } else if (sessionInfos[sessionTypes.AR].currentSession == session) {
+    // TODO(bsheedy): Replace this check if there's ever something like
+    // session.ar for checking if the session is AR-capable.
+    return sessionTypes.AR;
+  } else {
+    return sessionTypes.MAGIC_WINDOW;
+  }
+}
 
 function onRequestSession() {
-  xrDevice.requestSession({exclusive: true}).then( (session) => {
-    exclusiveSession = session;
-    onSessionStarted(session);
-  });
+  switch (sessionTypeToRequest) {
+    case sessionTypes.EXCLUSIVE:
+      xrDevice.requestSession({exclusive: true}).then( (session) => {
+        sessionInfos[sessionTypes.EXCLUSIVE].currentSession = session;
+        onSessionStarted(session);
+      });
+      break;
+    case sessionTypes.AR:
+      let sessionOptions = {
+        requestAR: true,
+        outputContext: webglCanvas.getContext('xrpresent'),
+      };
+      xrDevice.requestSession(sessionOptions).then((session) => {
+        sessionInfos[sessionTypes.AR].currentSession = session;
+        onSessionStarted(session);
+      });
+      break;
+    default:
+      throw 'Given unsupported WebXR session type enum ' + sessionTypeToRequest;
+  }
 }
 
 function onSessionStarted(session) {
@@ -45,7 +109,7 @@ function onSessionStarted(session) {
     let offscreenCanvas = document.createElement('canvas');
     gl = offscreenCanvas.getContext('webgl', glAttribs);
     if (!gl) {
-      console.error('Failed to get WebGL context');
+      throw 'Failed to get WebGL context';
     }
     gl.clearColor(0.0, 1.0, 0.0, 1.0);
     gl.enable(gl.DEPTH_TEST);
@@ -55,28 +119,21 @@ function onSessionStarted(session) {
 
   session.baseLayer = new XRWebGLLayer(session, gl);
   session.requestFrameOfReference('eye-level').then( (frameOfRef) => {
-    if (session.exclusive) {
-      exclusiveFrameOfRef = frameOfRef;
-    } else {
-      magicWindowFrameOfRef = frameOfRef;
-    }
+    sessionInfos[getSessionType(session)].currentFrameOfRef = frameOfRef;
     session.requestAnimationFrame(onXRFrame);
   });
 }
 
 function onSessionEnded(event) {
-  if (event.session.exclusive)
-    exclusiveSession = null
-  else
-    magicWindowSession = null;
+  sessionInfos[getSessionType(event.session)].clearSession();
 }
 
 function onXRFrame(t, frame) {
   let session = frame.session;
   session.requestAnimationFrame(onXRFrame);
-  let frameOfRef = session.exclusive ?
-                   exclusiveFrameOfRef :
-                   magicWindowFrameOfRef;
+
+  let frameOfRef = null;
+  frameOfRef = sessionInfos[getSessionType(session)].currentFrameOfRef;
   let pose = frame.getDevicePose(frameOfRef);
 
   // Exiting the rAF callback without dirtying the GL context is interpreted
@@ -87,22 +144,40 @@ function onXRFrame(t, frame) {
 
   gl.bindFramebuffer(gl.FRAMEBUFFER, session.baseLayer.framebuffer);
 
-  // If in an exclusive session, set canvas to blue. Otherwise, red.
-  if (session.exclusive) {
-    gl.clearColor(0.0, 0.0, 1.0, 1.0);
-    if (onExclusiveXRFrameCallback) {
-      onExclusiveXRFrameCallback(session, frame, gl);
-    }
-  } else {
-    if (onMagicWindowXRFrameCallback) {
-      onMagicWindowXRFrameCallback(session, frame);
-    }
-    gl.clearColor(1.0, 0.0, 0.0, 1.0);
+  // If in an exclusive session, set canvas to blue.
+  // If in an AR session, just draw the camera.
+  // Otherwise, red.
+  switch (getSessionType(session)) {
+    case sessionTypes.EXCLUSIVE:
+      gl.clearColor(0.0, 0.0, 1.0, 1.0);
+      if (onExclusiveXRFrameCallback) {
+        onExclusiveXRFrameCallback(session, frame, gl);
+      }
+      gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
+      break;
+    case sessionTypes.AR:
+      // Do nothing for now
+      break;
+    default:
+      if (onMagicWindowXRFrameCallback) {
+        onMagicWindowXRFrameCallback(session, frame);
+      }
+      gl.clearColor(1.0, 0.0, 0.0, 1.0);
+      gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
   }
-  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
+
   hasPresentedFrame = true;
 }
 
+function checkIfArSessionWouldTriggerPermissionPrompt() {
+  arSessionRequestWouldTriggerPermissionPrompt = null;
+  navigator.permissions.query({name: 'camera'}).then( (permission) => {
+    arSessionRequestWouldTriggerPermissionPrompt = permission.state == 'prompt';
+  }, () => {
+    throw 'Permission query rejected';
+  });
+}
+
 // Try to get an XRDevice and set up a non-exclusive session with it
 if (navigator.xr) {
   navigator.xr.requestDevice().then( (device) => {
@@ -113,11 +188,22 @@ if (navigator.xr) {
     // Set up the device to have a non-exclusive session (magic window) drawing
     // into the full screen canvas on the page
     let ctx = webglCanvas.getContext('xrpresent');
-    device.requestSession({outputContext: ctx}).then( (session) => {
-      onSessionStarted(session);
-    }).then( () => {
+    // WebXR for VR tests want a non-exclusive session to be automatically
+    // created on page load to reduce the amount of boilerplate code necessary.
+    // However, doing so during AR tests currently fails due to AR sessions
+    // always requiring a user gesture. So, allow a page to set a variable
+    // before loading this JavaScript file if they wish to skip the automatic
+    // non-exclusive session creation.
+    if (typeof shouldAutoCreateNonExclusiveSession === 'undefined'
+        || shouldAutoCreateNonExclusiveSession === true) {
+      device.requestSession({outputContext: ctx}).then( (session) => {
+        onSessionStarted(session);
+      }).then( () => {
+        initializationSteps['magicWindowStarted'] = true;
+      });
+    } else {
       initializationSteps['magicWindowStarted'] = true;
-    });
+    }
   }).then( () => {
     initializationSteps['getXRDevice'] = true;
   });