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/SymbolTable.h b/src/compiler/translator/SymbolTable.h
index dfc65cb..8ccb443 100644
--- a/src/compiler/translator/SymbolTable.h
+++ b/src/compiler/translator/SymbolTable.h
@@ -133,20 +133,20 @@
         type.setQualifier(qualifier);
     }
 
-    ConstantUnion *getConstPointer()
+    TConstantUnion *getConstPointer()
     { 
         if (!unionArray)
-            unionArray = new ConstantUnion[type.getObjectSize()];
+            unionArray = new TConstantUnion[type.getObjectSize()];
 
         return unionArray;
     }
 
-    ConstantUnion *getConstPointer() const
+    TConstantUnion *getConstPointer() const
     {
         return unionArray;
     }
 
-    void shareConstPointer(ConstantUnion *constArray)
+    void shareConstPointer(TConstantUnion *constArray)
     {
         if (unionArray == constArray)
             return;
@@ -160,7 +160,7 @@
     bool userType;
     // we are assuming that Pool Allocator will free the memory
     // allocated to unionArray when this object is destroyed.
-    ConstantUnion *unionArray;
+    TConstantUnion *unionArray;
 };
 
 // The function sub-class of symbols and the parser will need to