Update non-default constructors in shadervars.h.

Most of these constructors are unused. Remove the unused ones,
and change the usage of existing constructors to be consistent.

BUG=angle:466,697

Change-Id: I455dd314036e1dfcb8c4690bab577b81dd0e060c
Reviewed-on: https://chromium-review.googlesource.com/208355
Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Nicolas Capens <capn@chromium.org>
diff --git a/src/compiler/translator/ShaderLang.cpp b/src/compiler/translator/ShaderLang.cpp
index 6a801ea..db04d88 100644
--- a/src/compiler/translator/ShaderLang.cpp
+++ b/src/compiler/translator/ShaderLang.cpp
@@ -468,7 +468,7 @@
     std::vector<sh::ShaderVariable> variables;
     for (size_t ii = 0; ii < varInfoArraySize; ++ii)
     {
-        sh::ShaderVariable var(varInfoArray[ii].type, (sh::GLenum)0, "", varInfoArray[ii].size);
+        sh::ShaderVariable var(varInfoArray[ii].type, varInfoArray[ii].size);
         variables.push_back(var);
     }
     VariablePacker packer;