WebXR Hand Input: Flags, IDL and Blink stubs.

This change contains the flags, IDL definitions and blink stubs for the
WebXR Hand Input module.

https://immersive-web.github.io/webxr-hand-input/
https://github.com/immersive-web/webxr-hand-input/issues/

Subsequent changes will provide the Blink implementation, OpenXR device
implementation and test code.

Change-Id: I90169c4be02cf5daa29283a3fdf7fda6a4a2c319
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2623532
Commit-Queue: Lachlan Ford <laford@microsoft.com>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844283}

content/browser/xr/metrics/webxr_session_tracker.cc

@@ -80,6 +80,7 @@ void WebXRSessionTracker::ReportFeatureUsed(
     case XRSessionFeature::PLANE_DETECTION:
     case XRSessionFeature::DEPTH:
     case XRSessionFeature::IMAGE_TRACKING:
+    case XRSessionFeature::HAND_INPUT:
       // Not recording metrics for these features currently.
       // TODO(https://crbug.com/965729): Add metrics for the AR-related features
       // that are enabled by default.
@@ -121,6 +122,7 @@ void WebXRSessionTracker::SetFeatureRequest(
     case XRSessionFeature::PLANE_DETECTION:
     case XRSessionFeature::DEPTH:
     case XRSessionFeature::IMAGE_TRACKING:
+    case XRSessionFeature::HAND_INPUT:
       // Not recording metrics for these features currently.
       // TODO(https://crbug.com/965729): Add metrics for the AR-related features
       // that are enabled by default.

content/child/runtime_features.cc

@@ -213,6 +213,7 @@ void SetRuntimeFeaturesFromChromiumFeatures() {
     {wf::EnablePeriodicBackgroundSync, features::kPeriodicBackgroundSync},
     {wf::EnableWebXR, features::kWebXr},
     {wf::EnableWebXRARModule, features::kWebXrArModule},
+    {wf::EnableWebXRHandInput, features::kWebXrHandInput},
     {wf::EnableWebXRHitTest, features::kWebXrHitTest},
     {wf::EnableWebXRAnchors, features::kWebXrIncubations},
     {wf::EnableWebXRCameraAccess, features::kWebXrIncubations},

content/public/common/content_features.cc

@@ -856,6 +856,10 @@ const base::Feature kWebXr{"WebXR", base::FEATURE_ENABLED_BY_DEFAULT};
 const base::Feature kWebXrArModule{"WebXRARModule",
                                    base::FEATURE_ENABLED_BY_DEFAULT};
 
+// Enables access to articulated hand tracking sensor input.
+const base::Feature kWebXrHandInput{"WebXRHandInput",
+                                    base::FEATURE_DISABLED_BY_DEFAULT};
+
 // Enables access to raycasting against estimated XR scene geometry.
 const base::Feature kWebXrHitTest{"WebXRHitTest",
                                   base::FEATURE_ENABLED_BY_DEFAULT};

content/public/common/content_features.h

@@ -193,6 +193,7 @@ CONTENT_EXPORT extern const base::Feature kWebUIReportOnlyTrustedTypes;
 CONTENT_EXPORT extern const base::Feature kWebUsb;
 CONTENT_EXPORT extern const base::Feature kWebXr;
 CONTENT_EXPORT extern const base::Feature kWebXrArModule;
+CONTENT_EXPORT extern const base::Feature kWebXrHandInput;
 CONTENT_EXPORT extern const base::Feature kWebXrHitTest;
 CONTENT_EXPORT extern const base::Feature kWebXrIncubations;
 

device/vr/public/mojom/vr_service.mojom

@@ -66,6 +66,7 @@ enum XRSessionFeature {
   PLANE_DETECTION = 11, // Experimental feature.
   DEPTH = 12, // Experimental feature.
   IMAGE_TRACKING = 13, // Experimental feature.
+  HAND_INPUT = 14, // Experimental feature.
 };
 
 // These values are persisted to logs. Entries should not be renumbered and

third_party/blink/public/platform/web_runtime_features.h

@@ -173,6 +173,7 @@ class WebRuntimeFeatures {
   BLINK_PLATFORM_EXPORT static void EnableWebXRARModule(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebXRCameraAccess(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebXRDepth(bool);
+  BLINK_PLATFORM_EXPORT static void EnableWebXRHandInput(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebXRHitTest(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebXRImageTracking(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebXRLightEstimation(bool);

third_party/blink/renderer/bindings/generated_in_modules.gni

@@ -1204,6 +1204,8 @@ generated_enumeration_sources_in_modules = [
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_environment_blend_mode.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_eye.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_eye.h",
+  "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_hand_joint.cc",
+  "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_hand_joint.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_handedness.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_handedness.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_hit_test_trackable_type.cc",
@@ -2209,6 +2211,8 @@ generated_interface_sources_in_modules = [
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_dom_overlay_state.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_frame.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_frame.h",
+  "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_hand.cc",
+  "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_hand.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_hit_test_result.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_hit_test_result.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_hit_test_source.cc",
@@ -2223,6 +2227,10 @@ generated_interface_sources_in_modules = [
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_input_source_event.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_input_sources_change_event.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_input_sources_change_event.h",
+  "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_joint_pose.cc",
+  "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_joint_pose.h",
+  "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_joint_space.cc",
+  "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_joint_space.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_layer.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_layer.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/modules/v8/v8_xr_light_estimate.cc",

third_party/blink/renderer/bindings/idl_in_modules.gni

@@ -1008,6 +1008,9 @@ static_idl_files_in_modules = get_path_info(
           "//third_party/blink/renderer/modules/xr/xr_dom_overlay_state.idl",
           "//third_party/blink/renderer/modules/xr/xr_frame.idl",
           "//third_party/blink/renderer/modules/xr/xr_frame_request_callback.idl",
+          "//third_party/blink/renderer/modules/xr/xr_hand.idl",
+          "//third_party/blink/renderer/modules/xr/xr_joint_pose.idl",
+          "//third_party/blink/renderer/modules/xr/xr_joint_space.idl",
           "//third_party/blink/renderer/modules/xr/xr_hit_test_options_init.idl",
           "//third_party/blink/renderer/modules/xr/xr_hit_test_result.idl",
           "//third_party/blink/renderer/modules/xr/xr_hit_test_source.idl",

third_party/blink/renderer/modules/xr/BUILD.gn

@@ -33,6 +33,8 @@ blink_modules_sources("xr") {
     "xr_frame_request_callback_collection.h",
     "xr_grip_space.cc",
     "xr_grip_space.h",
+    "xr_hand.cc",
+    "xr_hand.h",
     "xr_hit_test_result.cc",
     "xr_hit_test_result.h",
     "xr_hit_test_source.cc",
@@ -47,6 +49,10 @@ blink_modules_sources("xr") {
     "xr_input_source_event.h",
     "xr_input_sources_change_event.cc",
     "xr_input_sources_change_event.h",
+    "xr_joint_pose.cc",
+    "xr_joint_pose.h",
+    "xr_joint_space.cc",
+    "xr_joint_space.h",
     "xr_layer.cc",
     "xr_layer.h",
     "xr_light_estimate.cc",

third_party/blink/renderer/modules/xr/idls.gni

@@ -11,6 +11,9 @@ modules_idl_files = [
   "xr_depth_information.idl",
   "xr_dom_overlay_state.idl",
   "xr_frame.idl",
+  "xr_hand.idl",
+  "xr_joint_pose.idl",
+  "xr_joint_space.idl",
   "xr_image_tracking_result.idl",
   "xr_input_source.idl",
   "xr_input_source_array.idl",

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

@@ -7,6 +7,7 @@
 #include "third_party/blink/renderer/core/dom/dom_exception.h"
 #include "third_party/blink/renderer/modules/xr/xr_hit_test_source.h"
 #include "third_party/blink/renderer/modules/xr/xr_input_source.h"
+#include "third_party/blink/renderer/modules/xr/xr_joint_space.h"
 #include "third_party/blink/renderer/modules/xr/xr_light_estimate.h"
 #include "third_party/blink/renderer/modules/xr/xr_light_probe.h"
 #include "third_party/blink/renderer/modules/xr/xr_plane_set.h"
@@ -381,6 +382,28 @@ HeapVector<Member<XRImageTrackingResult>> XRFrame::getImageTrackingResults(
   return session_->ImageTrackingResults(exception_state);
 }
 
+XRJointPose* XRFrame::getJointPose(XRJointSpace* joint,
+                                   XRSpace* baseSpace,
+                                   ExceptionState& exception_state) {
+  NOTIMPLEMENTED();
+  return nullptr;
+}
+
+bool XRFrame::fillJointRadii(HeapVector<Member<XRJointSpace>>& jointSpaces,
+                             NotShared<DOMFloat32Array> radii,
+                             ExceptionState& exception_state) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
+bool XRFrame::fillPoses(HeapVector<Member<XRSpace>>& spaces,
+                        XRSpace* baseSpace,
+                        NotShared<DOMFloat32Array> transforms,
+                        ExceptionState& exception_state) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
 void XRFrame::Trace(Visitor* visitor) const {
   visitor->Trace(session_);
   ScriptWrappable::Trace(visitor);

third_party/blink/renderer/modules/xr/xr_frame.h

@@ -9,6 +9,8 @@
 
 #include "device/vr/public/mojom/vr_service.mojom-blink-forward.h"
 #include "third_party/blink/renderer/bindings/core/v8/script_promise.h"
+#include "third_party/blink/renderer/bindings/core/v8/v8_dom_matrix.h"
+#include "third_party/blink/renderer/modules/xr/xr_joint_pose.h"
 #include "third_party/blink/renderer/platform/bindings/script_state.h"
 #include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
 #include "third_party/blink/renderer/platform/heap/handle.h"
@@ -24,8 +26,10 @@ class XRHitTestResult;
 class XRHitTestSource;
 class XRImageTrackingResult;
 class XRInputSource;
+class XRJointPose;
 class XRLightEstimate;
 class XRLightProbe;
+class XRJointSpace;
 class XRPlaneSet;
 class XRPose;
 class XRReferenceSpace;
@@ -79,6 +83,17 @@ class XRFrame final : public ScriptWrappable {
   HeapVector<Member<XRImageTrackingResult>> getImageTrackingResults(
       ExceptionState&);
 
+  XRJointPose* getJointPose(XRJointSpace* joint,
+                            XRSpace* baseSpace,
+                            ExceptionState& exception_state);
+  bool fillJointRadii(HeapVector<Member<XRJointSpace>>& jointSpaces,
+                      NotShared<DOMFloat32Array> radii,
+                      ExceptionState& exception_state);
+  bool fillPoses(HeapVector<Member<XRSpace>>& spaces,
+                 XRSpace* baseSpace,
+                 NotShared<DOMFloat32Array> transforms,
+                 ExceptionState& exception_state);
+
  private:
   std::unique_ptr<TransformationMatrix> GetAdjustedPoseMatrix(XRSpace*) const;
   XRPose* GetTargetRayPose(XRInputSource*, XRSpace*) const;

third_party/blink/renderer/modules/xr/xr_frame.idl

@@ -32,6 +32,13 @@
   [RuntimeEnabled=WebXRImageTracking, RaisesException]
   FrozenArray<XRImageTrackingResult> getImageTrackingResults();
 
+  [RuntimeEnabled=WebXRHandInput, RaisesException]
+  XRJointPose? getJointPose(XRJointSpace joint, XRSpace baseSpace);
+  [RuntimeEnabled=WebXRHandInput, RaisesException]
+  boolean fillJointRadii(sequence<XRJointSpace> jointSpaces, Float32Array radii);
+  [RuntimeEnabled=WebXRHandInput, RaisesException]
+  boolean fillPoses(sequence<XRSpace> spaces, XRSpace baseSpace, Float32Array transforms);
+
   // More details about the real-world understanding APIs can be found here:
   // https://github.com/immersive-web/real-world-geometry/blob/master/plane-detection-explainer.md
   [RuntimeEnabled=WebXRPlaneDetection, RaisesException]

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

+// Copyright 2020 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 "third_party/blink/renderer/modules/xr/xr_hand.h"
+#include "third_party/blink/renderer/modules/xr/xr_input_source.h"
+#include "third_party/blink/renderer/modules/xr/xr_joint_pose.h"
+#include "third_party/blink/renderer/modules/xr/xr_joint_space.h"
+
+namespace blink {
+
+unsigned int XRHand::size() const {
+  NOTIMPLEMENTED();
+  return 0;
+}
+
+XRJointSpace* XRHand::get(const String& key) {
+  NOTIMPLEMENTED();
+  return nullptr;
+}
+
+XRHand::IterationSource* XRHand::StartIteration(ScriptState*, ExceptionState&) {
+  NOTIMPLEMENTED();
+  return nullptr;
+}
+
+void XRHand::Trace(Visitor* visitor) const {
+  ScriptWrappable::Trace(visitor);
+}
+
+}  // namespace blink

third_party/blink/renderer/modules/xr/xr_hand.h

+// Copyright 2020 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 THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_HAND_H_
+#define THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_HAND_H_
+
+#include "device/vr/public/mojom/vr_service.mojom-blink.h"
+#include "third_party/blink/renderer/bindings/core/v8/iterable.h"
+#include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
+#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
+
+namespace blink {
+
+class XRJointSpace;
+
+class XRHand : public ScriptWrappable,
+               public PairIterable<String, Member<XRJointSpace>> {
+  DEFINE_WRAPPERTYPEINFO();
+
+ public:
+  XRHand() = default;
+  ~XRHand() override = default;
+
+  unsigned int size() const;
+  XRJointSpace* get(const String& key);
+
+  void Trace(Visitor*) const override;
+
+ private:
+  using Iterationsource =
+      PairIterable<String, Member<XRJointSpace>>::IterationSource;
+  IterationSource* StartIteration(ScriptState*, ExceptionState&) override;
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_HAND_H_

third_party/blink/renderer/modules/xr/xr_hand.idl

+// Copyright 2020 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.
+
+//https://immersive-web.github.io/webxr-hand-input/#idl-index
+enum XRHandJoint {
+  "wrist",
+  "thumb-metacarpal",
+  "thumb-phalanx-proximal",
+  "thumb-phalanx-distal",
+  "thumb-tip",
+  "index-finger-metacarpal",
+  "index-finger-phalanx-proximal",
+  "index-finger-phalanx-intermediate",
+  "index-finger-phalanx-distal",
+  "index-finger-tip",
+  "middle-finger-metacarpal",
+  "middle-finger-phalanx-proximal",
+  "middle-finger-phalanx-intermediate",
+  "middle-finger-phalanx-distal",
+  "middle-finger-tip",
+  "ring-finger-metacarpal",
+  "ring-finger-phalanx-proximal",
+  "ring-finger-phalanx-intermediate",
+  "ring-finger-phalanx-distal",
+  "ring-finger-tip",
+  "pinky-finger-metacarpal",
+  "pinky-finger-phalanx-proximal",
+  "pinky-finger-phalanx-intermediate",
+  "pinky-finger-phalanx-distal",
+  "pinky-finger-tip"
+};
+
+//https://immersive-web.github.io/webxr-hand-input/#idl-index
+[
+    SecureContext,
+    Exposed=Window,
+    RuntimeEnabled=WebXRHandInput
+] interface XRHand {
+    iterable<XRHandJoint, XRJointSpace>;
+
+    readonly attribute unsigned long size;
+    XRJointSpace get(XRHandJoint key);
+};

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

@@ -14,6 +14,7 @@
 #include "third_party/blink/renderer/core/input/event_handling_util.h"
 #include "third_party/blink/renderer/core/layout/hit_test_location.h"
 #include "third_party/blink/renderer/modules/xr/xr_grip_space.h"
+#include "third_party/blink/renderer/modules/xr/xr_hand.h"
 #include "third_party/blink/renderer/modules/xr/xr_input_source_event.h"
 #include "third_party/blink/renderer/modules/xr/xr_session.h"
 #include "third_party/blink/renderer/modules/xr/xr_session_event.h"
@@ -129,6 +130,7 @@ XRInputSource::XRInputSource(const XRInputSource& other)
           MakeGarbageCollected<XRTargetRaySpace>(other.session_, this)),
       grip_space_(MakeGarbageCollected<XRGripSpace>(other.session_, this)),
       gamepad_(other.gamepad_),
+      hand_(other.hand_),
       mojo_from_input_(
           TryGetTransformationMatrix(other.mojo_from_input_.get())),
       input_from_pointer_(
@@ -614,6 +616,7 @@ void XRInputSource::Trace(Visitor* visitor) const {
   visitor->Trace(target_ray_space_);
   visitor->Trace(grip_space_);
   visitor->Trace(gamepad_);
+  visitor->Trace(hand_);
   ScriptWrappable::Trace(visitor);
 }
 

third_party/blink/renderer/modules/xr/xr_input_source.h

@@ -23,6 +23,7 @@ namespace blink {
 
 class Element;
 class XRGripSpace;
+class XRHand;
 class XRInputSourceEvent;
 class XRSession;
 class XRSpace;
@@ -49,6 +50,8 @@ class XRInputSource : public ScriptWrappable, public Gamepad::Client {
 
   XRSession* session() const { return session_; }
 
+  XRHand* hand() const { return hand_; }
+
   const String handedness() const;
   const String targetRayMode() const;
   bool emulatedPosition() const { return state_.emulated_position; }
@@ -161,6 +164,7 @@ class XRInputSource : public ScriptWrappable, public Gamepad::Client {
   Member<XRTargetRaySpace> target_ray_space_;
   Member<XRGripSpace> grip_space_;
   Member<Gamepad> gamepad_;
+  Member<XRHand> hand_{nullptr};
 
   // Input device pose in mojo space. This is the grip pose for
   // tracked controllers, and the viewer pose for screen input.

third_party/blink/renderer/modules/xr/xr_input_source.idl

@@ -24,5 +24,6 @@ enum XRTargetRayMode {
   [SameObject] readonly attribute XRSpace targetRaySpace;
   [SameObject] readonly attribute XRSpace? gripSpace;
   [SameObject, Measure] readonly attribute Gamepad? gamepad;
+  [SameObject, RuntimeEnabled=WebXRHandInput] readonly attribute XRHand? hand;
   [SameObject, SaveSameObject] readonly attribute FrozenArray<DOMString> profiles;
 };

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

+// Copyright 2020 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 "third_party/blink/renderer/modules/xr/xr_joint_pose.h"
+#include "third_party/blink/renderer/modules/xr/xr_pose.h"
+
+namespace blink {
+
+XRJointPose::XRJointPose(const TransformationMatrix& transform,
+                         bool emulatedPosition,
+                         float radius)
+    : XRPose(transform, emulatedPosition), radius_(radius) {}
+
+}  // namespace blink

third_party/blink/renderer/modules/xr/xr_joint_pose.h

+// Copyright 2020 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 THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_JOINT_POSE_H_
+#define THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_JOINT_POSE_H_
+
+#include "device/vr/public/mojom/vr_service.mojom-blink.h"
+#include "third_party/blink/renderer/modules/xr/xr_pose.h"
+#include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
+#include "third_party/blink/renderer/platform/transforms/transformation_matrix.h"
+
+namespace blink {
+
+class XRJointPose : public XRPose {
+  DEFINE_WRAPPERTYPEINFO();
+
+ public:
+  XRJointPose(const TransformationMatrix& transform,
+              bool emulatedPosition,
+              float radius);
+
+  float radius() const { return radius_; }
+
+ private:
+  float radius_;
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_JOINT_POSE_H_

third_party/blink/renderer/modules/xr/xr_joint_pose.idl

+// Copyright 2020 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.
+
+[
+    SecureContext,
+    Exposed=Window,
+    RuntimeEnabled=WebXRHandInput
+] interface XRJointPose : XRPose {
+  readonly attribute float radius;
+};

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

+// Copyright 2020 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 "third_party/blink/renderer/modules/xr/xr_joint_space.h"
+#include "third_party/blink/renderer/modules/xr/xr_space.h"
+
+namespace blink {
+
+XRJointSpace::XRJointSpace(
+    XRSession* session,
+    std::unique_ptr<TransformationMatrix> mojo_from_joint,
+    String joint_name,
+    float radius)
+    : XRSpace(session),
+      mojo_from_joint_space_(std::move(mojo_from_joint)),
+      joint_name_(joint_name),
+      radius_(radius) {}
+
+base::Optional<TransformationMatrix> XRJointSpace::MojoFromNative() {
+  return *mojo_from_joint_space_.get();
+}
+
+bool XRJointSpace::EmulatedPosition() const {
+  NOTIMPLEMENTED();
+  return false;
+}
+
+base::Optional<device::mojom::blink::XRNativeOriginInformation>
+XRJointSpace::NativeOrigin() const {
+  NOTIMPLEMENTED();
+  return base::nullopt;
+}
+
+bool XRJointSpace::IsStationary() const {
+  return false;
+}
+
+std::string XRJointSpace::ToString() const {
+  return "XRJointSpace";
+}
+
+void XRJointSpace::Trace(Visitor* visitor) const {
+  XRSpace::Trace(visitor);
+}
+
+}  // namespace blink

third_party/blink/renderer/modules/xr/xr_joint_space.h

+// Copyright 2020 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 THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_JOINT_SPACE_H_
+#define THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_JOINT_SPACE_H_
+
+#include "base/optional.h"
+#include "device/vr/public/mojom/vr_service.mojom-blink.h"
+#include "third_party/blink/renderer/modules/xr/xr_native_origin_information.h"
+#include "third_party/blink/renderer/modules/xr/xr_space.h"
+#include "third_party/blink/renderer/platform/transforms/transformation_matrix.h"
+
+namespace blink {
+
+class XRSession;
+
+class XRJointSpace : public XRSpace {
+  DEFINE_WRAPPERTYPEINFO();
+
+ public:
+  XRJointSpace(XRSession* session,
+               std::unique_ptr<TransformationMatrix> mojo_from_joint,
+               String joint_name,
+               float radius);
+
+  float GetRadius() const { return radius_; }
+  const String& jointName() const { return joint_name_; }
+
+  base::Optional<TransformationMatrix> MojoFromNative() override;
+  bool EmulatedPosition() const override;
+
+  base::Optional<device::mojom::blink::XRNativeOriginInformation> NativeOrigin()
+      const override;
+
+  bool IsStationary() const override;
+
+  std::string ToString() const override;
+
+  void Trace(Visitor*) const override;
+
+ private:
+  const std::unique_ptr<TransformationMatrix> mojo_from_joint_space_;
+  const String joint_name_;
+  const float radius_;
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_MODULES_XR_XR_JOINT_SPACE_H_

third_party/blink/renderer/modules/xr/xr_joint_space.idl

+// Copyright 2020 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.
+[
+    SecureContext,
+    Exposed=Window,
+    RuntimeEnabled=WebXRHandInput
+] interface XRJointSpace : XRSpace {
+    readonly attribute XRHandJoint jointName;
+};

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

@@ -304,6 +304,7 @@ void XRSession::MetricsReporter::ReportFeatureUsed(
     case XRSessionFeature::PLANE_DETECTION:
     case XRSessionFeature::DEPTH:
     case XRSessionFeature::IMAGE_TRACKING:
+    case XRSessionFeature::HAND_INPUT:
       // Not recording metrics for these features currently.
       break;
   }

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

@@ -150,6 +150,9 @@ base::Optional<device::mojom::XRSessionFeature> StringToXRSessionFeature(
   } else if (RuntimeEnabledFeatures::WebXRImageTrackingEnabled(context) &&
              feature_string == "image-tracking") {
     return device::mojom::XRSessionFeature::IMAGE_TRACKING;
+  } else if (RuntimeEnabledFeatures::WebXRHandInputEnabled(context) &&
+             feature_string == "hand-tracking") {
+    return device::mojom::XRSessionFeature::HAND_INPUT;
   }
 
   return base::nullopt;
@@ -169,6 +172,7 @@ bool IsFeatureValidForMode(device::mojom::XRSessionFeature feature,
     case device::mojom::XRSessionFeature::REF_SPACE_UNBOUNDED:
     case device::mojom::XRSessionFeature::HIT_TEST:
     case device::mojom::XRSessionFeature::ANCHORS:
+    case device::mojom::XRSessionFeature::HAND_INPUT:
       return mode == device::mojom::blink::XRSessionMode::kImmersiveVr ||
              mode == device::mojom::blink::XRSessionMode::kImmersiveAr;
     case device::mojom::XRSessionFeature::DOM_OVERLAY:
@@ -223,6 +227,7 @@ bool HasRequiredFeaturePolicy(const ExecutionContext* context,
     case device::mojom::XRSessionFeature::PLANE_DETECTION:
     case device::mojom::XRSessionFeature::DEPTH:
     case device::mojom::XRSessionFeature::IMAGE_TRACKING:
+    case device::mojom::XRSessionFeature::HAND_INPUT:
       return context->IsFeatureEnabled(
           mojom::blink::FeaturePolicyFeature::kWebXr,
           ReportOptions::kReportOnFailure);

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

@@ -393,6 +393,10 @@ void WebRuntimeFeatures::EnableWebXRDepth(bool enable) {
   RuntimeEnabledFeatures::SetWebXRDepthEnabled(enable);
 }
 
+void WebRuntimeFeatures::EnableWebXRHandInput(bool enable) {
+  RuntimeEnabledFeatures::SetWebXRHandInputEnabled(enable);
+}
+
 void WebRuntimeFeatures::EnableWebXRHitTest(bool enable) {
   RuntimeEnabledFeatures::SetWebXRHitTestEnabled(enable);
 }

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -2250,6 +2250,11 @@
       depends_on: ["WebXRARModule"],
       status: "experimental",
     },
+    {
+      name: "WebXRHandInput",
+      depends_on: ["WebXRARModule"],
+      status: "experimental"
+    },
     {
       name: "WebXRHitTest",
       depends_on: ["WebXRARModule"],

third_party/blink/web_tests/external/wpt/webxr/hand-input/idlharness.https.window-expected.txt

-This is a testharness.js-based test.
-PASS idl_test setup
-PASS idl_test validation
-PASS Partial interface XRInputSource: original interface defined
-PASS Partial interface XRInputSource: member names are unique
-PASS Partial interface XRFrame: original interface defined
-PASS Partial interface XRFrame: member names are unique
-FAIL XRHand interface: existence and properties of interface object assert_own_property: self does not have own property "XRHand" expected property "XRHand" missing
-FAIL XRHand interface object length assert_own_property: self does not have own property "XRHand" expected property "XRHand" missing
-FAIL XRHand interface object name assert_own_property: self does not have own property "XRHand" expected property "XRHand" missing
-FAIL XRHand interface: existence and properties of interface prototype object assert_own_property: self does not have own property "XRHand" expected property "XRHand" missing
-FAIL XRHand interface: existence and properties of interface prototype object's "constructor" property assert_own_property: self does not have own property "XRHand" expected property "XRHand" missing
-FAIL XRHand interface: existence and properties of interface prototype object's @@unscopables property assert_own_property: self does not have own property "XRHand" expected property "XRHand" missing
-FAIL XRHand interface: iterable<XRHandJoint, XRJointSpace> Cannot read property 'prototype' of undefined
-FAIL XRHand interface: attribute size assert_own_property: self does not have own property "XRHand" expected property "XRHand" missing
-FAIL XRHand interface: operation get(XRHandJoint) assert_own_property: self does not have own property "XRHand" expected property "XRHand" missing
-FAIL XRJointSpace interface: existence and properties of interface object assert_own_property: self does not have own property "XRJointSpace" expected property "XRJointSpace" missing
-FAIL XRJointSpace interface object length assert_own_property: self does not have own property "XRJointSpace" expected property "XRJointSpace" missing
-FAIL XRJointSpace interface object name assert_own_property: self does not have own property "XRJointSpace" expected property "XRJointSpace" missing
-FAIL XRJointSpace interface: existence and properties of interface prototype object assert_own_property: self does not have own property "XRJointSpace" expected property "XRJointSpace" missing
-FAIL XRJointSpace interface: existence and properties of interface prototype object's "constructor" property assert_own_property: self does not have own property "XRJointSpace" expected property "XRJointSpace" missing
-FAIL XRJointSpace interface: existence and properties of interface prototype object's @@unscopables property assert_own_property: self does not have own property "XRJointSpace" expected property "XRJointSpace" missing
-FAIL XRJointSpace interface: attribute jointName assert_own_property: self does not have own property "XRJointSpace" expected property "XRJointSpace" missing
-FAIL XRJointPose interface: existence and properties of interface object assert_own_property: self does not have own property "XRJointPose" expected property "XRJointPose" missing
-FAIL XRJointPose interface object length assert_own_property: self does not have own property "XRJointPose" expected property "XRJointPose" missing
-FAIL XRJointPose interface object name assert_own_property: self does not have own property "XRJointPose" expected property "XRJointPose" missing
-FAIL XRJointPose interface: existence and properties of interface prototype object assert_own_property: self does not have own property "XRJointPose" expected property "XRJointPose" missing
-FAIL XRJointPose interface: existence and properties of interface prototype object's "constructor" property assert_own_property: self does not have own property "XRJointPose" expected property "XRJointPose" missing
-FAIL XRJointPose interface: existence and properties of interface prototype object's @@unscopables property assert_own_property: self does not have own property "XRJointPose" expected property "XRJointPose" missing
-FAIL XRJointPose interface: attribute radius assert_own_property: self does not have own property "XRJointPose" expected property "XRJointPose" missing
-FAIL XRFrame interface: operation getJointPose(XRJointSpace, XRSpace) assert_own_property: interface prototype object missing non-static operation expected property "getJointPose" missing
-FAIL XRFrame interface: operation fillJointRadii(sequence<XRJointSpace>, Float32Array) assert_own_property: interface prototype object missing non-static operation expected property "fillJointRadii" missing
-FAIL XRFrame interface: operation fillPoses(sequence<XRSpace>, XRSpace, Float32Array) assert_own_property: interface prototype object missing non-static operation expected property "fillPoses" missing
-FAIL XRInputSource interface: attribute hand assert_true: The prototype object must have a property "hand" expected true got false
-Harness: the test ran to completion.
-

third_party/blink/web_tests/webexposed/global-interface-listing-expected.txt

@@ -10502,13 +10502,26 @@ interface XRFrame
     getter trackedAnchors
     method constructor
     method createAnchor
+    method fillJointRadii
+    method fillPoses
     method getDepthInformation
     method getHitTestResults
     method getHitTestResultsForTransientInput
     method getImageTrackingResults
+    method getJointPose
     method getLightEstimate
     method getPose
     method getViewerPose
+interface XRHand
+    attribute @@toStringTag
+    getter size
+    method @@iterator
+    method constructor
+    method entries
+    method forEach
+    method get
+    method keys
+    method values
 interface XRHitTestResult
     attribute @@toStringTag
     method constructor
@@ -10529,6 +10542,7 @@ interface XRInputSource
     attribute @@toStringTag
     getter gamepad
     getter gripSpace
+    getter hand
     getter handedness
     getter profiles
     getter targetRayMode
@@ -10554,6 +10568,14 @@ interface XRInputSourcesChangeEvent : Event
     getter removed
     getter session
     method constructor
+interface XRJointPose : XRPose
+    attribute @@toStringTag
+    getter radius
+    method constructor
+interface XRJointSpace : XRSpace
+    attribute @@toStringTag
+    getter jointName
+    method constructor
 interface XRLayer : EventTarget
     attribute @@toStringTag
     method constructor