SurfaceFlinger: add composer 2.4 vsync api to DisplayHardware

Add the new functions to DisplayHardware wrappers. The following CLs
will do something useful with the new functionality.

Test: rev up composer to 2.4 and test refresh rate switching
Bug: 141329414
Change-Id: Iaf98d0abc56dd393845b16c87dd92b0bad582c0f
diff --git a/libs/vr/libvrflinger/hardware_composer.h b/libs/vr/libvrflinger/hardware_composer.h
index 989ce35..8698814 100644
--- a/libs/vr/libvrflinger/hardware_composer.h
+++ b/libs/vr/libvrflinger/hardware_composer.h
@@ -375,6 +375,12 @@
     hardware::Return<void> onRefresh(Hwc2::Display display) override;
     hardware::Return<void> onVsync(Hwc2::Display display,
                                    int64_t timestamp) override;
+    hardware::Return<void> onVsync_2_4(
+        Hwc2::Display display, int64_t timestamp,
+        Hwc2::VsyncPeriodNanos vsyncPeriodNanos) override;
+    hardware::Return<void> onVsyncPeriodTimingChanged(
+        Hwc2::Display display,
+        const Hwc2::VsyncPeriodChangeTimeline& updatedTimeline) override;
 
     bool GotFirstHotplug() { return got_first_hotplug_; }
     void SetVsyncService(const sp<VsyncService>& vsync_service);