Add enum type for supported HDR metadata

Test: Builds

Bug: 112508112
Bug: 120990898
Change-Id: If6e01bad9275b057d9bdbe963a25b7a26b7198a2
diff --git a/libs/nativewindow/include/android/hdr_metadata.h b/libs/nativewindow/include/android/hdr_metadata.h
index 7e1313b..88772a9 100644
--- a/libs/nativewindow/include/android/hdr_metadata.h
+++ b/libs/nativewindow/include/android/hdr_metadata.h
@@ -33,6 +33,15 @@
  */
 
 /**
+ * HDR metadata standards that are supported by Android.
+ */
+enum AHdrMetadataType : uint32_t {
+    HDR10_SMPTE2086 = 1,
+    HDR10_CTA861_3 = 2,
+    HDR10PLUS_SEI = 3,
+};
+
+/**
  * Color is defined in CIE XYZ coordinates.
  */
 struct AColor_xy {