Added support for EXT_frag_depth

This change also required that support be added for associating built-in
variables with an extension, similar to how functions could be associated with
extensions previously.

R=alokp@chromium.org

Review URL: https://codereview.appspot.com/9827044

git-svn-id: https://angleproject.googlecode.com/svn/trunk@2248 736b8ea6-26fd-11df-bfd4-992fa37f6226

TRAC #23333
Authored-by: bajones@chromium.org
Signed-off-by: Shannon Woods
Signed-off-by Nicolas Capens
Merged-by: Jamie Madill
diff --git a/src/compiler/SymbolTable.cpp b/src/compiler/SymbolTable.cpp
index 2c96e35..47ebb94 100644
--- a/src/compiler/SymbolTable.cpp
+++ b/src/compiler/SymbolTable.cpp
@@ -225,10 +225,9 @@
 void TSymbolTableLevel::relateToExtension(const char* name, const TString& ext)
 {
     for (tLevel::iterator it = level.begin(); it != level.end(); ++it) {
-        if (it->second->isFunction()) {
-            TFunction* function = static_cast<TFunction*>(it->second);
-            if (function->getName() == name)
-                function->relateToExtension(ext);
+        TSymbol* symbol = it->second;
+        if (symbol->getName() == name) {
+            symbol->relateToExtension(ext);
         }
     }
 }