Move ParsePsshdata function into base class.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=225035658

util/error_space.h

@@ -49,11 +49,11 @@ class ErrorSpaceImpl : public ErrorSpace {
   // pointer to stateless static methods, so that clients of ErrorSpaceImpl are
   // safe to have constexpr global instances.
   static std::string SpaceNameImpl(const ErrorSpace* /*space*/) {
-    return T::SpaceName();
+    return T::space_name();
   }
 
   static std::string CodeToStringImpl(const ErrorSpace* /*space*/, int code) {
-    return T::CodeToString(code);
+    return T::code_to_string(code);
   }
 };