[WGSL] Preserve binary operation precedence

https://bugs.webkit.org/show_bug.cgi?id=255517
rdar://108136098

Reviewed by Mike Wyrzykowski.

Binary operations should be parenthesized when serializing in order
to preserve their precedence.

* Source/WebGPU/WGSL/Metal/MetalFunctionWriter.cpp:
(WGSL::Metal::FunctionDefinitionWriter::visit):

Canonical link: https://commits.webkit.org/263092@main

Source/WebGPU/WGSL/Metal/MetalFunctionWriter.cpp

@@ -508,6 +508,7 @@ void FunctionDefinitionWriter::visit(AST::UnaryExpression& unary)
 
 void FunctionDefinitionWriter::visit(AST::BinaryExpression& binary)
 {
+    m_stringBuilder.append("(");
     visit(binary.leftExpression());
     switch (binary.operation()) {
     case AST::BinaryOperation::Add:
@@ -567,6 +568,7 @@ void FunctionDefinitionWriter::visit(AST::BinaryExpression& binary)
         break;
     }
     visit(binary.rightExpression());
+    m_stringBuilder.append(")");
 }
 
 void FunctionDefinitionWriter::visit(AST::PointerDereferenceExpression& pointerDereference)

Tools/TestWebKitAPI/Tests/WGSL/MetalGenerationTests.cpp

@@ -83,7 +83,7 @@ using namespace metal;
 [[fragment]] void function0(unsigned parameter0 [[sample_mask]], unsigned parameter1 [[sample_id]], vec<float, 4> parameter2 [[position]])
 {
     vec<float, 4> local0 = parameter2;
-    unsigned local1 = parameter1 + parameter0;
+    unsigned local1 = (parameter1 + parameter0);
 }
 
 )"_s);