Add libvrflinger for use in SurfaceFlinger

A separate CL uses this code from SurfaceFlinger.

Bug: None
Test: Manually ran modified SurfaceFlinger
Change-Id: I34588df1365588c0a0265e1e2325e3dd5516206a
diff --git a/libs/vr/libvrflinger/display_service.h b/libs/vr/libvrflinger/display_service.h
new file mode 100644
index 0000000..ebd97de
--- /dev/null
+++ b/libs/vr/libvrflinger/display_service.h
@@ -0,0 +1,107 @@
+#ifndef ANDROID_DVR_SERVICES_DISPLAYD_DISPLAY_SERVICE_H_
+#define ANDROID_DVR_SERVICES_DISPLAYD_DISPLAY_SERVICE_H_
+
+#include <pdx/service.h>
+#include <private/dvr/buffer_hub_client.h>
+#include <private/dvr/display_rpc.h>
+#include <private/dvr/late_latch.h>
+
+#include <functional>
+#include <iterator>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "acquired_buffer.h"
+#include "display_surface.h"
+#include "epoll_event_dispatcher.h"
+#include "hardware_composer.h"
+
+namespace android {
+namespace dvr {
+
+// DisplayService implements the displayd display service over ServiceFS.
+class DisplayService : public pdx::ServiceBase<DisplayService> {
+ public:
+  std::string DumpState(size_t max_length) override;
+
+  void OnChannelClose(pdx::Message& message,
+                      const std::shared_ptr<pdx::Channel>& channel) override;
+  int HandleMessage(pdx::Message& message) override;
+
+  std::shared_ptr<DisplaySurface> GetDisplaySurface(int surface_id) const;
+  std::vector<std::shared_ptr<DisplaySurface>> GetDisplaySurfaces() const;
+  std::vector<std::shared_ptr<DisplaySurface>> GetVisibleDisplaySurfaces()
+      const;
+
+  // Updates the list of actively displayed surfaces. This must be called after
+  // any change to client/manager attributes that affect visibility or z order.
+  int UpdateActiveDisplaySurfaces();
+
+  template <class A>
+  void ForEachDisplaySurface(A action) const {
+    ForEachChannel([action](const ChannelIterator::value_type& pair) mutable {
+      auto surface = std::static_pointer_cast<SurfaceChannel>(pair.second);
+      if (surface->type() == SurfaceTypeEnum::Normal)
+        action(std::static_pointer_cast<DisplaySurface>(surface));
+    });
+  }
+
+  using DisplayConfigurationUpdateNotifier = std::function<void(void)>;
+  void SetDisplayConfigurationUpdateNotifier(
+      DisplayConfigurationUpdateNotifier notifier);
+
+  using VSyncCallback = HardwareComposer::VSyncCallback;
+  void SetVSyncCallback(VSyncCallback callback) {
+    hardware_composer_.SetVSyncCallback(callback);
+  }
+
+  HWCDisplayMetrics GetDisplayMetrics() {
+    return hardware_composer_.display_metrics();
+  }
+
+  void SetActive(bool activated) {
+    if (activated) {
+      hardware_composer_.Resume();
+    } else {
+      hardware_composer_.Suspend();
+    }
+  }
+
+ private:
+  friend BASE;
+  friend DisplaySurface;
+
+  friend class VrDisplayStateService;
+
+  DisplayService();
+  DisplayService(android::Hwc2::Composer* hidl);
+
+  SystemDisplayMetrics OnGetMetrics(pdx::Message& message);
+  int OnCreateSurface(pdx::Message& message, int width, int height,
+                      int format, int usage, DisplaySurfaceFlags flags);
+
+  DisplayRPC::ByteBuffer OnGetEdsCapture(pdx::Message& message);
+
+  int OnEnterVrMode(pdx::Message& message);
+  int OnExitVrMode(pdx::Message& message);
+  void OnSetViewerParams(pdx::Message& message, const ViewerParams& view_params);
+
+  // Called by DisplaySurface to signal that a surface property has changed and
+  // the display manager should be notified.
+  void NotifyDisplayConfigurationUpdate();
+
+  int HandleSurfaceMessage(pdx::Message& message);
+
+  DisplayService(const DisplayService&) = delete;
+  void operator=(const DisplayService&) = delete;
+
+  EpollEventDispatcher dispatcher_;
+  HardwareComposer hardware_composer_;
+  DisplayConfigurationUpdateNotifier update_notifier_;
+};
+
+}  // namespace dvr
+}  // namespace android
+
+#endif  // ANDROID_DVR_SERVICES_DISPLAYD_DISPLAY_SERVICE_H_