Add new ASTC pixel config

src/gpu/gl/GrGpuGL.cpp

Index: src/gpu/gl/GrGpuGL.cpp
diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index b66feb27c06f954f691260dea5672b35edfd2c4d..3a2be13aacb95737690a1f2dd7ec7e5f4cd35ad5 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -2698,11 +2698,17 @@ bool GrGpuGL::configToGLFormats(GrPixelConfig config,
         case kR11_EAC_GrPixelConfig:
             *internalFormat = GR_GL_COMPRESSED_R11;
             break;
+
+        case kASTC_12x12_GrPixelConfig:
+            *internalFormat = GR_GL_COMPRESSED_RGBA_ASTC_12x12;
+            break;
+
         case kRGBA_float_GrPixelConfig:
             *internalFormat = GR_GL_RGBA32F;
             *externalFormat = GR_GL_RGBA;
             *externalType = GR_GL_FLOAT;
             break;
+
         default:
             return false;
     }