Update XrContextHelperOpenXR.h to obtain native extension from the global navigator object (#185)

* move to custom branch

* obtain xr context off of navigator

* merge master into babylonnative

* address review comments

* move to most recent commit

* move to most recent babylonnative commit

Author: C. M. Barth

Modules/@babylonjs/react-native-windows/windows/include/XrContextHelperOpenXR.h

@@ -6,18 +6,29 @@
 
 namespace BabylonReactNative
 {
-    bool TryGetXrContext(facebook::jsi::Runtime& jsiRuntime, const facebook::jsi::Value& xrSession, IXrContextOpenXR*& xrContext)
+    bool TryGetXrContext(facebook::jsi::Runtime& jsiRuntime, IXrContextOpenXR*& xrContext)
     {
         xrContext = nullptr;
-        if (!xrSession.isObject() ||
-            !xrSession.asObject(jsiRuntime).hasProperty(jsiRuntime, "nativeXrContext") ||
-            !xrSession.asObject(jsiRuntime).hasProperty(jsiRuntime, "nativeXrContextType") ||
-            xrSession.asObject(jsiRuntime).getProperty(jsiRuntime, "nativeXrContextType").asString(jsiRuntime).utf8(jsiRuntime) != "OpenXR")
+        if (!jsiRuntime.global().hasProperty(jsiRuntime, "navigator"))
         {
             return false;
         }
 
-        auto nativeExtensionPtr = static_cast<uintptr_t>(xrSession.asObject(jsiRuntime).getProperty(jsiRuntime, "nativeXrContext").asNumber());
+        auto navigator{ jsiRuntime.global().getProperty(jsiRuntime, "navigator").asObject(jsiRuntime) };
+        if (!navigator.hasProperty(jsiRuntime, "xr"))
+        {
+            return false;
+        }
+
+        auto nativeXr{ navigator.getProperty(jsiRuntime, "xr").asObject(jsiRuntime) };
+        if (!nativeXr.hasProperty(jsiRuntime, "nativeXrContext") ||
+            !nativeXr.hasProperty(jsiRuntime, "nativeXrContextType") ||
+            nativeXr.getProperty(jsiRuntime, "nativeXrContextType").asString(jsiRuntime).utf8(jsiRuntime) != "OpenXR")
+        {
+            return false;
+        }
+
+        auto nativeExtensionPtr = static_cast<uintptr_t>(nativeXr.getProperty(jsiRuntime, "nativeXrContext").asNumber());
         xrContext = reinterpret_cast<IXrContextOpenXR*>(nativeExtensionPtr);
         return true;
     }