translator: Store symbol type in TField.

This allows us to keep a separate symbol type for each field in a
struct. This can allow us to assign internal names to struct types.
It could also allow us to add internal fields to user defined stucts.

Bug: angleproject:2665
Change-Id: I6a129107d9db66c54b98b07684c3ead5801712ba
Reviewed-on: https://chromium-review.googlesource.com/1101565
Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/compiler/translator/ParseContext.cpp b/src/compiler/translator/ParseContext.cpp
index e3df66a..f8df136 100644
--- a/src/compiler/translator/ParseContext.cpp
+++ b/src/compiler/translator/ParseContext.cpp
@@ -4714,7 +4714,8 @@
             type->makeArrays(*declarator->arraySizes());
         }
 
-        TField *field = new TField(type, declarator->name(), declarator->line());
+        TField *field =
+            new TField(type, declarator->name(), declarator->line(), SymbolType::UserDefined);
         checkIsBelowStructNestingLimit(typeSpecifier.getLine(), *field);
         fieldList->push_back(field);
     }