Only expose VR controllers as Gamepads when appropriate

VR runtime-backed controllers should only be exposed when WebXR
or WebVR APIs are available.

BUG=830935

Change-Id: I354be9e62e90e7acac3fd712fc3497c141373a47
Reviewed-on: https://chromium-review.googlesource.com/1003732
Commit-Queue: David Dorwin <ddorwin@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550094}

device/gamepad/public/cpp/gamepad.h

@@ -138,6 +138,8 @@ class Gamepad {
   GamepadHand hand;
 
   unsigned display_id;
+
+  bool is_xr = false;
 };
 
 #pragma pack(pop)

device/vr/android/gvr/cardboard_gamepad_data_fetcher.cc

@@ -85,6 +85,7 @@ void CardboardGamepadDataFetcher::GetGamepadData(bool devices_changed_hint) {
     // This is the first time we've seen this device, so do some one-time
     // initialization
     pad.connected = true;
+    pad.is_xr = true;
     CopyToUString(pad.id, Gamepad::kIdLengthCap,
                   base::UTF8ToUTF16("Cardboard Button"));
     CopyToUString(pad.mapping, Gamepad::kMappingLengthCap,

device/vr/android/gvr/gvr_gamepad_data_fetcher.cc

@@ -95,6 +95,8 @@ void GvrGamepadDataFetcher::GetGamepadData(bool devices_changed_hint) {
 
     pad.display_id = display_id_;
 
+    pad.is_xr = true;
+
     pad.hand =
         provided_data.right_handed ? GamepadHand::kRight : GamepadHand::kLeft;
   }

device/vr/oculus/oculus_gamepad_data_fetcher.cc

@@ -77,6 +77,7 @@ void SetTouchData(PadState* state,
   if (!state->is_initialized) {
     state->is_initialized = true;
     pad.connected = true;
+    pad.is_xr = true;
     pad.pose.not_null = true;
     pad.pose.has_orientation = true;
     pad.pose.has_position = true;
@@ -225,6 +226,7 @@ void OculusGamepadDataFetcher::GetGamepadData(bool devices_changed_hint) {
         state->is_initialized = true;
         swprintf(pad.id, Gamepad::kIdLengthCap, L"Oculus Remote");
         pad.connected = true;
+        pad.is_xr = true;
         pad.display_id = display_id_;
       }
       pad.timestamp = input_state.TimeInSeconds;

device/vr/openvr/openvr_gamepad_data_fetcher.cc

@@ -94,6 +94,7 @@ void OpenVRGamepadDataFetcher::GetGamepadData(bool devices_changed_hint) {
                                        sizeof(controller_state))) {
       pad.timestamp = controller_state.unPacketNum;
       pad.connected = true;
+      pad.is_xr = true;
 
       pad.pose.not_null = true;
 

ppapi/shared_impl/ppb_gamepad_shared.h

@@ -112,8 +112,12 @@ struct WebKitGamepad {
   // Gamepad Extensions member, unused by ppapi.
   WebKitGamepadHand hand;
 
-  // ID of the VRDisplay this gamepad is associated with, if any.
+  // ID of the VRDisplay this gamepad is associated with, if any. Unused by
+  // ppapi.
   unsigned display_id;
+
+  // True if this controller is backed by VR APIs, unused by ppapi.
+  bool is_xr;
 };
 
 // This must match the definition of blink::Gamepads. The GamepadHost unit

third_party/blink/renderer/modules/gamepad/navigator_gamepad.cc

@@ -31,6 +31,7 @@
 #include "third_party/blink/renderer/core/dom/events/event.h"
 #include "third_party/blink/renderer/core/frame/local_frame.h"
 #include "third_party/blink/renderer/core/frame/navigator.h"
+#include "third_party/blink/renderer/core/origin_trials/origin_trials.h"
 #include "third_party/blink/renderer/core/page/page.h"
 #include "third_party/blink/renderer/modules/gamepad/gamepad_dispatcher.h"
 #include "third_party/blink/renderer/modules/gamepad/gamepad_event.h"
@@ -87,14 +88,31 @@ static void SampleGamepad(unsigned index,
 }
 
 template <typename GamepadType, typename ListType>
-static void SampleGamepads(ListType* into) {
+static void SampleGamepads(ListType* into, const ExecutionContext* context) {
   device::Gamepads gamepads;
 
   GamepadDispatcher::Instance().SampleGamepads(gamepads);
 
   for (unsigned i = 0; i < device::Gamepads::kItemsLengthCap; ++i) {
     device::Gamepad& web_gamepad = gamepads.items[i];
-    if (web_gamepad.connected) {
+
+    bool hide_xr_gamepad = false;
+    if (web_gamepad.is_xr) {
+      bool webxr_enabled =
+          (context && OriginTrials::webXRGamepadSupportEnabled(context) &&
+           OriginTrials::webXREnabled(context));
+      bool webvr_enabled = (context && OriginTrials::webVREnabled(context));
+
+      if (!webxr_enabled && !webvr_enabled) {
+        // If neither WebXR nor WebVR are enabled, we should not expose XR-
+        // backed gamepads.
+        hide_xr_gamepad = true;
+      }
+    }
+
+    if (hide_xr_gamepad) {
+      into->Set(i, nullptr);
+    } else if (web_gamepad.connected) {
       GamepadType* gamepad = into->item(i);
       if (!gamepad)
         gamepad = GamepadType::Create();
@@ -261,6 +279,9 @@ void NavigatorGamepad::DidRemoveGamepadEventListeners() {
 }
 
 void NavigatorGamepad::SampleAndCheckConnectedGamepads() {
+  ExecutionContext* execution_context =
+      DomWindow() ? DomWindow()->GetExecutionContext() : nullptr;
+
   if (StartUpdatingIfAttached()) {
     if (!gamepads_)
       gamepads_ = GamepadList::Create();
@@ -270,7 +291,7 @@ void NavigatorGamepad::SampleAndCheckConnectedGamepads() {
 
       // Compare the current sample with the old data and enqueue connection
       // events for any differences.
-      SampleGamepads<Gamepad>(gamepads_back_.Get());
+      SampleGamepads<Gamepad>(gamepads_back_.Get(), execution_context);
       if (CheckConnectedGamepads(gamepads_.Get(), gamepads_back_.Get())) {
         // If we had any disconnected gamepads, we can't overwrite gamepads_
         // because the Gamepad object from the old buffer is reused as the
@@ -283,7 +304,7 @@ void NavigatorGamepad::SampleAndCheckConnectedGamepads() {
         dispatch_one_event_runner_->RunAsync();
       }
     }
-    SampleGamepads<Gamepad>(gamepads_.Get());
+    SampleGamepads<Gamepad>(gamepads_.Get(), execution_context);
   }
 }