| # XR Browser implementation |
| _For a more high level overview of the entire WebXR stack, please refer to |
| [components/webxr](https://source.chromium.org/chromium/chromium/src/+/main:components/webxr/README.md)._ |
| |
| This folder contains trusted XR code. It is largely responsible for either |
| communicating with other trusted code, or to broker connections and |
| communication between either other trusted code or the renderer process and the |
| various XR device runtimes (which are hosted in a separate process). |
| |
| The primary entrypoint is the [`VRServiceImpl`][vr service impl], which |
| implements the [`VRService`][vr service] mojom interface. This service is |
| responsible for brokering connections between the renderer process and the |
| device process, both for the sake of starting up an XR Session, as well as |
| simply querying support for a session. Each browsing context ends up creating |
| its own [`VRService`][vr service]. A [`VRServiceImpl`][vr service impl] instance, |
| when tracking a session, also leans on code from the ./metrics directory to log |
| various metrics about that session, both at creation and termination. |
| |
| The [`XRRuntimeManager`][runtime manager] is a singleton component which |
| maintains references to [`BrowserXrRuntime`][xr runtime] objects representing |
| the various devices and/or sensor groups that could back an XR Session. The |
| [`XRRuntimeManager`][runtime manager] is responsible for tracking the state of |
| the hardware and aiding the multiple [`VRServices`][vr service impl] with |
| communicating/tracking this state. |
| |
| When necessary, [`XRFrameSinkClient`][xr frame sink] instances aid communication |
| with viz for runtimes which utilize that component to manage their own |
| compositing. |
| |
| Some chrome-specific customizations based on this content implementation can be |
| found in [chrome/browser/vr](https://chromium.googlesource.com/chromium/src/+/HEAD/chrome/browser/vr) |
| |
| [vr service impl]: https://chromium.googlesource.com/chromium/src/+/HEAD/content/browser/xr/service/vr_service_impl.h |
| [vr service]: https://chromium.googlesource.com/chromium/src/+/HEAD/device/vr/public/mojom/vr_service.mojom |
| [runtime manager]: https://chromium.googlesource.com/chromium/src/+/HEAD/content/browser/xr/service/xr_runtime_manager_impl.h |
| [xr runtime]: https://chromium.googlesource.com/chromium/src/+/HEAD/content/browser/xr/service/browser_xr_runtime.h |
| [xr frame sink]: https://chromium.googlesource.com/chromium/src/+/HEAD/content/browser/xr/service/xr_frame_sink_client_impl.h |
