Clean up ValidateMaxParameters

It doesn't need to use a traverser, since all function definitions can
be found simply by iterating over the children of the root node.

BUG=angleproject:2040
TEST=angle_unittests

Change-Id: I18a98eff9710485c0cdce73e7fffe124f7d7afb2
Reviewed-on: https://chromium-review.googlesource.com/508791
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/compiler/translator/Compiler.h b/src/compiler/translator/Compiler.h
index 2614199..95544c9 100644
--- a/src/compiler/translator/Compiler.h
+++ b/src/compiler/translator/Compiler.h
@@ -156,7 +156,7 @@
     // This function should only be applied to vertex shaders.
     void initializeGLPosition(TIntermBlock *root);
     // Return true if the maximum expression complexity is below the limit.
-    bool limitExpressionComplexity(TIntermNode *root);
+    bool limitExpressionComplexity(TIntermBlock *root);
     // Get built-in extensions with default behavior.
     const TExtensionBehavior &getExtensionBehavior() const;
     const char *getSourcePath() const;