[wasm-test] WasmModuleBuilder.addCustomSection in the JS builder API.

test/mjsunit/wasm/js-api.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --expose-wasm --allow-natives-syntax
 
 if ((typeof drainJobQueue) != "function") {
   drainJobQueue = () => { %RunMicrotasks() };
 }
 
@@ skipping 274 matching lines @@
     'first argument must be a WebAssembly.Module');
 assertErrorMessage(
     () => moduleCustomSections(emptyModule), TypeError,
     'second argument must be a String');
 assertErrorMessage(
     () => moduleCustomSections(emptyModule, 3), TypeError,
     'second argument must be a String');
 
 let customSectionModuleBinary2 = (() => {
   let builder = new WasmModuleBuilder();
-  builder.addExplicitSection([kUnknownSectionCode, 3, 1, 'x'.charCodeAt(0), 2]);
-  builder.addExplicitSection([
-    kUnknownSectionCode, 6, 3, 'f'.charCodeAt(0), 'o'.charCodeAt(0),
-    'o'.charCodeAt(0), 66, 77
-  ]);
-  builder.addExplicitSection([
-    kUnknownSectionCode, 7, 3, 'f'.charCodeAt(0), 'o'.charCodeAt(0),
-    'o'.charCodeAt(0), 91, 92, 93
-  ]);
-  builder.addExplicitSection([
-    kUnknownSectionCode, 7, 3, 'f'.charCodeAt(0), 'o'.charCodeAt(0),
-    'x'.charCodeAt(0), 99, 99, 99
-  ]);
+  builder.addCustomSection('x', [2]);
+  builder.addCustomSection('foo', [66, 77]);
+  builder.addCustomSection('foo', [91, 92, 93]);
+  builder.addCustomSection('fox', [99, 99, 99]);
   return new Int8Array(builder.toBuffer());
 })();
 var arr = moduleCustomSections(new Module(customSectionModuleBinary2), 'x');
 assertEq(arr instanceof Array, true);
 assertEq(arr.length, 1);
 assertArrayBuffer(arr[0], [2]);
 var arr = moduleCustomSections(new Module(customSectionModuleBinary2), 'foo');
 assertEq(arr instanceof Array, true);
 assertEq(arr.length, 2);
 assertArrayBuffer(arr[0], [66, 77]);
@@ skipping 388 matching lines @@
     assertTrue(result.instance instanceof Instance);
   }
 }
 assertInstantiateSuccess(emptyModule);
 assertInstantiateSuccess(emptyModuleBinary);
 assertInstantiateSuccess(emptyModuleBinary.buffer);
 assertInstantiateSuccess(importingModule, {'': {f: () => {}}});
 assertInstantiateSuccess(importingModuleBinary, {"":{f:()=>{}}});
 assertInstantiateSuccess(importingModuleBinary.buffer, {"":{f:()=>{}}});
 assertInstantiateSuccess(memoryImportingModuleBinary, {"": {"my_memory": scratch_memory}});