Remove EOpInternalFunctionCall

It's cleaner to mark internal functions by using the TName class,
similarly to TIntermSymbol.

TEST=angle_unittests
BUG=angleproject:1116

Change-Id: I12a03a3dea42b3fc571fa25a1b11d0161f24de72
Reviewed-on: https://chromium-review.googlesource.com/291621
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/compiler/translator/IntermNode.cpp b/src/compiler/translator/IntermNode.cpp
index 1d26947..cdc53c2 100644
--- a/src/compiler/translator/IntermNode.cpp
+++ b/src/compiler/translator/IntermNode.cpp
@@ -365,7 +365,7 @@
     }
     // ESSL 3.0 spec section 8: textureSize always gets highp precision.
     // All other functions that take a sampler are assumed to be texture functions.
-    if (mName.find("textureSize") == 0)
+    if (mName.getString().find("textureSize") == 0)
         mType.setPrecision(EbpHigh);
     else
         mType.setPrecision(precision);