Change comma nodes to TIntermBinary Comma nodes always have just two parameters. If there's an expression with several commas in the middle, it's parsed as a tree of comma operations. It makes more sense to represent it as a binary node rather than an aggregate node. After this patch, TIntermAggregate is still used for function prototypes, function parameter lists, function calls, and variable and invariant declarations. BUG=angleproject:1490 TEST=angle_unittests, angle_end2end_tests Change-Id: I66be10624bf27bcf25987b4d93958d4a07600771 Reviewed-on: https://chromium-review.googlesource.com/397320 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>