gpu: support GL_TEXTURE_CUBE_MAP destination target to Copy(Sub)TextureCHROMIUM.

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 806b297326f2584689c005b0fea476621d692fad..3e25c6f9767a4277bb29fc0c457dae97cce37d69 100644
--- a/gpu/command_buffer/common/gles2_cmd_utils.h
+++ b/gpu/command_buffer/common/gles2_cmd_utils.h
@@ -137,6 +137,8 @@ class GLES2_UTILS_EXPORT GLES2Util {
 
   static size_t GLTargetToFaceIndex(uint32_t target);
 
+  static uint32_t GLTextureTargetToBindingTarget(uint32_t textarget);
+
   static uint32_t GetGLReadPixelsImplementationFormat(
       uint32_t internal_format);