Experimental: Add R_16 and RG_1616 to Ganesh (take 2)

This is to support the P016 and P010 YUV formats. Initially, only Vulkan and GL support these formats.

Change-Id: I4e896f1d3fb32207227a755517ae5a00a58e6045
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/219403
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrCaps.cpp b/src/gpu/GrCaps.cpp
index 7543820..9a1222e 100644
--- a/src/gpu/GrCaps.cpp
+++ b/src/gpu/GrCaps.cpp
@@ -156,6 +156,9 @@
         case kRGBA_half_GrPixelConfig: return "RGBAHalf";
         case kRGBA_half_Clamped_GrPixelConfig: return "RGBAHalfClamped";
         case kRGB_ETC1_GrPixelConfig: return "RGBETC1";
+        // Experimental (for P016 and P010)
+        case kR_16_GrPixelConfig: return "R16";
+        case kRG_1616_GrPixelConfig: return "RG1616";
     }
     SK_ABORT("Invalid pixel config");
     return "<invalid>";