Clean up TIntermTraverser usage

Remove default parameters from TIntermTraverser.

Also clean up a few dead function declarations in traversers.

TEST=angle_unittests, angle_end2end_tests
BUG=angleproject:1037

Change-Id: I8d126c6c2d5b53e8b14e23e3d102f204a59323b3
Reviewed-on: https://chromium-review.googlesource.com/275184
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Tested-by: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/compiler/translator/ValidateLimitations.cpp b/src/compiler/translator/ValidateLimitations.cpp
index e247a28..efb0601 100644
--- a/src/compiler/translator/ValidateLimitations.cpp
+++ b/src/compiler/translator/ValidateLimitations.cpp
@@ -26,7 +26,11 @@
 {
   public:
     ValidateConstIndexExpr(TLoopStack& stack)
-        : mValid(true), mLoopStack(stack) {}
+        : TIntermTraverser(true, false, false),
+          mValid(true),
+          mLoopStack(stack)
+    {
+    }
 
     // Returns true if the parsed node represents a constant index expression.
     bool isValid() const { return mValid; }
@@ -51,7 +55,8 @@
 
 ValidateLimitations::ValidateLimitations(sh::GLenum shaderType,
                                          TInfoSinkBase &sink)
-    : mShaderType(shaderType),
+    : TIntermTraverser(true, false, false),
+      mShaderType(shaderType),
       mSink(sink),
       mNumErrors(0)
 {