Split TIntermFunctionPrototype from TIntermAggregate

Function prototypes now have their own class TIntermFunctionPrototype.
It's only used for prototypes, not function parameter lists.

TIntermAggregate is still used for parameter lists and function calls.

BUGS=angleproject:1490
TEST=angle_unittests

Change-Id: I6e246ad00a29c2335bd2ab7f61cf73fe463b74bb
Reviewed-on: https://chromium-review.googlesource.com/427944
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/EmulatePrecision.h b/src/compiler/translator/EmulatePrecision.h
index 6642140..ed15395 100644
--- a/src/compiler/translator/EmulatePrecision.h
+++ b/src/compiler/translator/EmulatePrecision.h
@@ -32,6 +32,7 @@
     bool visitAggregate(Visit visit, TIntermAggregate *node) override;
     bool visitInvariantDeclaration(Visit visit, TIntermInvariantDeclaration *node) override;
     bool visitDeclaration(Visit visit, TIntermDeclaration *node) override;
+    bool visitFunctionPrototype(Visit visit, TIntermFunctionPrototype *node) override;
 
     void writeEmulationHelpers(TInfoSinkBase &sink,
                                const int shaderVersion,