Add symbol table function to get TFunction for a built-in op

Built-in function parameter qualifiers are stored in the symbol table.
Some AST traversers need the qualifier information for ops to
determine whether a node is being written to. Add an utility function
that maps a TIntermAggregate node to a symbol table entry, so that the
traversers can get to this information in a convenient way.

This will be necessary for adding more built-ins that have out
parameters from ESSL 3.10.

BUG=angleproject:1730
TEST=angle_unittests

Change-Id: I4bc622d70b2326a04cc858ff1258c22320c590dc
Reviewed-on: https://chromium-review.googlesource.com/431109
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/translator/ValidateMultiviewWebGL.h b/src/compiler/translator/ValidateMultiviewWebGL.h
index 0d8d11b..371a03d 100644
--- a/src/compiler/translator/ValidateMultiviewWebGL.h
+++ b/src/compiler/translator/ValidateMultiviewWebGL.h
@@ -17,11 +17,14 @@
 {
 class TDiagnostics;
 class TIntermBlock;
+class TSymbolTable;
 
 // Check for errors and output error messages with diagnostics.
 // Returns true if there are no errors.
 bool ValidateMultiviewWebGL(TIntermBlock *root,
                             sh::GLenum shaderType,
+                            const TSymbolTable &symbolTable,
+                            int shaderVersion,
                             bool multiview2,
                             TDiagnostics *diagnostics);