Clean up direct access of ShaderVariable::arraySize

This change is pure refactoring. It's intended to help with adding
support for arrays of arrays.

BUG=angleproject:2125
TEST=angle_unittests

Change-Id: I82881a98c3c476fd6666a551ce6be255ae0de4cf
Reviewed-on: https://chromium-review.googlesource.com/733127
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/compiler/translator/Compiler.cpp b/src/compiler/translator/Compiler.cpp
index b7af2d7..f18fd30 100644
--- a/src/compiler/translator/Compiler.cpp
+++ b/src/compiler/translator/Compiler.cpp
@@ -1020,7 +1020,7 @@
 void TCompiler::initializeGLPosition(TIntermBlock *root)
 {
     InitVariableList list;
-    sh::ShaderVariable var(GL_FLOAT_VEC4, 0);
+    sh::ShaderVariable var(GL_FLOAT_VEC4);
     var.name = "gl_Position";
     list.push_back(var);
     InitializeVariables(root, list, symbolTable, shaderVersion, extensionBehavior);