Rename ConstantUnion to TConstantUnion.

This clarified that we're using the Pool allocator/deallocator for
this type.

BUG=angleproject:993

Change-Id: If8c95f6054d07291e7014be0d4e35766ba2e943b
Reviewed-on: https://chromium-review.googlesource.com/269131
Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
diff --git a/src/compiler/translator/Intermediate.h b/src/compiler/translator/Intermediate.h
index 3efb3bd..74a3f89 100644
--- a/src/compiler/translator/Intermediate.h
+++ b/src/compiler/translator/Intermediate.h
@@ -49,9 +49,9 @@
         TIntermTyped *condition, const TSourceLoc &line);
     TIntermTyped *addComma(
         TIntermTyped *left, TIntermTyped *right, const TSourceLoc &);
-    TIntermConstantUnion *addConstantUnion(ConstantUnion *, const TType &, const TSourceLoc &);
+    TIntermConstantUnion *addConstantUnion(TConstantUnion *, const TType &, const TSourceLoc &);
     // TODO(zmo): Get rid of default value.
-    bool parseConstTree(const TSourceLoc &, TIntermNode *, ConstantUnion *,
+    bool parseConstTree(const TSourceLoc &, TIntermNode *, TConstantUnion *,
                         TOperator, TType, bool singleConstantParam = false);
     TIntermNode *addLoop(TLoopType, TIntermNode *, TIntermTyped *, TIntermTyped *,
                          TIntermNode *, const TSourceLoc &);