Fix ReadPixels implementation specific read format/type on desktop GL.

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 69efb0b4caf35741e020f22f608c67ccd13a191e..bfd07f1926480b5c59773088434753361bb430f1 100644
--- a/gpu/command_buffer/common/gles2_cmd_utils.h
+++ b/gpu/command_buffer/common/gles2_cmd_utils.h
@@ -69,6 +69,11 @@ class GLES2_UTILS_EXPORT GLES2Util {
     kRGBA = kRGB | kAlpha
   };
 
+  enum TargetESVersion {
+    kES2,
+    kES3
+  };
+
   struct EnumToString {
     uint32_t value;
     const char* name;
@@ -137,10 +142,12 @@ class GLES2_UTILS_EXPORT GLES2Util {
 
   static size_t GLTargetToFaceIndex(uint32_t target);
 
-  static uint32_t GetPreferredGLReadPixelsFormat(uint32_t internal_format);
+  static uint32_t GetGLReadPixelsImplementationFormat(
+      uint32_t internal_format, TargetESVersion target_es_version);
 
-  static uint32_t GetPreferredGLReadPixelsType(
-      uint32_t internal_format, uint32_t texture_type);
+  static uint32_t GetGLReadPixelsImplementationType(
+      uint32_t internal_format, uint32_t texture_type,
+      TargetESVersion target_es_version);
 
   // Returns a bitmask for the channels the given format supports.
   // See ChannelBits.