WebXR: Require user activation to create AR sessions

BUG=835039

Change-Id: If61cc049fd0f8d18de7bdd7df7ff71a9dd8f699b
Reviewed-on: https://chromium-review.googlesource.com/1041217
Commit-Queue: Bill Orr <billorr@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556234}

content/child/runtime_features.cc

@@ -213,6 +213,9 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   if (base::FeatureList::IsEnabled(features::kWebXrGamepadSupport))
     WebRuntimeFeatures::EnableWebXRGamepadSupport(true);
 
+  if (base::FeatureList::IsEnabled(features::kWebXrHitTest))
+    WebRuntimeFeatures::EnableWebXRHitTest(true);
+
   if (command_line.HasSwitch(switches::kDisablePresentationAPI))
     WebRuntimeFeatures::EnablePresentationAPI(false);
 

third_party/WebKit/LayoutTests/xr/xrDevice_requestSession_exclusive_no_gesture.html

@@ -13,6 +13,6 @@ let fakeDevices = fakeXRDevices();
 promise_test( (t) => {
   setFakeDevices([fakeDevices["FakeGooglePixelPhone"]]);
   return navigator.xr.requestDevice().then( (device) =>
-    promise_rejects(t, 'InvalidStateError', device.requestSession({ exclusive: true })));
+    promise_rejects(t, 'SecurityError', device.requestSession({ exclusive: true })));
 }, "requestSession with an exclusive session outside of a user gesture rejects");
 </script>

third_party/blink/public/platform/web_runtime_features.h

@@ -152,6 +152,7 @@ class WebRuntimeFeatures {
   BLINK_PLATFORM_EXPORT static void EnableWebUsb(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebVR(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebXR(bool);
+  BLINK_PLATFORM_EXPORT static void EnableWebXRHitTest(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebXRGamepadSupport(bool);
   BLINK_PLATFORM_EXPORT static void EnableXSLT(bool);
   BLINK_PLATFORM_EXPORT static void ForceOverlayFullscreenVideo(bool);

third_party/blink/renderer/modules/xr/xr_device.cc

@@ -128,7 +128,17 @@ ScriptPromise XRDevice::requestSession(
     if (!Frame::HasTransientUserActivation(doc ? doc->GetFrame() : nullptr)) {
       return ScriptPromise::RejectWithDOMException(
           script_state,
-          DOMException::Create(kInvalidStateError, kRequestNotInUserGesture));
+          DOMException::Create(kSecurityError, kRequestNotInUserGesture));
+    }
+  }
+
+  // All AR sessions require a user gesture.
+  // TODO(https://crbug.com/828321): Use session options instead.
+  if (RuntimeEnabledFeatures::WebXRHitTestEnabled()) {
+    if (!Frame::HasTransientUserActivation(doc ? doc->GetFrame() : nullptr)) {
+      return ScriptPromise::RejectWithDOMException(
+          script_state,
+          DOMException::Create(kSecurityError, kRequestNotInUserGesture));
     }
   }
 

third_party/blink/renderer/platform/exported/web_runtime_features.cc

@@ -364,6 +364,10 @@ void WebRuntimeFeatures::EnableWebXRGamepadSupport(bool enable) {
   RuntimeEnabledFeatures::SetWebXRGamepadSupportEnabled(enable);
 }
 
+void WebRuntimeFeatures::EnableWebXRHitTest(bool enable) {
+  RuntimeEnabledFeatures::SetWebXRHitTestEnabled(enable);
+}
+
 void WebRuntimeFeatures::EnablePresentationAPI(bool enable) {
   RuntimeEnabledFeatures::SetPresentationEnabled(enable);
 }

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1365,6 +1365,10 @@
       implied_by: ["GamepadExtensions"],
       status: "experimental",
     },
+    {
+      name: "WebXRHitTest",
+      status: "experimental",
+    },
     {
       name: "WorkerNosniffBlock",
       status: "test",