Make unique id counter a member of TSymbolTable

This makes unique id counting thread-safe.

BUG=angleproject:624
TEST=angle_unittests

Change-Id: Ie0f2c7e574470b39750d37d2181c790bc874b275
Reviewed-on: https://chromium-review.googlesource.com/570419
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/translator/Initialize.cpp b/src/compiler/translator/Initialize.cpp
index 2f93307..3b0589f 100644
--- a/src/compiler/translator/Initialize.cpp
+++ b/src/compiler/translator/Initialize.cpp
@@ -689,7 +689,7 @@
     fields->push_back(far);
     fields->push_back(diff);
     TStructure *depthRangeStruct =
-        new TStructure(NewPoolTString("gl_DepthRangeParameters"), fields);
+        new TStructure(&symbolTable, NewPoolTString("gl_DepthRangeParameters"), fields);
     symbolTable.insertStructType(COMMON_BUILTINS, depthRangeStruct);
     TType depthRangeType(depthRangeStruct);
     depthRangeType.setQualifier(EvqUniform);