Reland of Select correct copy method for DoCopySubTexture

gpu/command_buffer/common/gles2_cmd_utils.h

Index: gpu/command_buffer/common/gles2_cmd_utils.h
diff --git a/gpu/command_buffer/common/gles2_cmd_utils.h b/gpu/command_buffer/common/gles2_cmd_utils.h
index 8d0f16baba0fa205bdfa407f56a41ed171c6cd35..969a7245060578b393d50448dbb026afce99cd0c 100644
--- a/gpu/command_buffer/common/gles2_cmd_utils.h
+++ b/gpu/command_buffer/common/gles2_cmd_utils.h
@@ -243,8 +243,11 @@ class GLES2_UTILS_EXPORT GLES2Util {
   static bool IsIntegerFormat(uint32_t internal_format);
   static bool IsFloatFormat(uint32_t internal_format);
   static uint32_t ConvertToSizedFormat(uint32_t format, uint32_t type);
-
   static bool IsSizedColorFormat(uint32_t internal_format);
+
+  // Infer color encoding from internalformat
+  static int GetColorEncodingFromInternalFormat(uint32_t internalformat);
+
   static void GetColorFormatComponentSizes(
       uint32_t internal_format, uint32_t type, int* r, int* g, int* b, int* a);