Add a preliminary R11 EAC compressor

src/utils/SkTextureCompressor.h

Index: src/utils/SkTextureCompressor.h
diff --git a/src/utils/SkTextureCompressor.h b/src/utils/SkTextureCompressor.h
index 7dda66b0880205f7af42812a30de2fbd5bee20bc..35b9b864307405122f1e1d6e9c313b5376f4237a 100644
--- a/src/utils/SkTextureCompressor.h
+++ b/src/utils/SkTextureCompressor.h
@@ -16,10 +16,11 @@ class SkData;
 namespace SkTextureCompressor {
     // Various texture compression formats that we support.
     enum Format {
-        // Alpha only format.
+        // Alpha only formats.
         kLATC_Format,
+        kR11_EAC_Format,
 
-        kLast_Format = kLATC_Format
+        kLast_Format = kR11_EAC_Format
     };
     static const int kFormatCnt = kLast_Format + 1;