[wasm] Implement correct 2-level namespace for imports.

test/mjsunit/wasm/test-wasm-module-builder.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
 
 load('test/mjsunit/wasm/wasm-constants.js');
 load('test/mjsunit/wasm/wasm-module-builder.js');
 
 var debug = true;
 
 function instantiate(buffer, ffi) {
   return new WebAssembly.Instance(WebAssembly.Module(buffer), ffi);
 }
 
 (function BasicTest() {
     let builder = new WasmModuleBuilder();
     builder.addMemory(1, 2, false);
     builder.addFunction("foo", kSig_i_v)
         .addBody([kExprI8Const, 11])
         .exportAs("blarg");
 
     var buffer = builder.toBuffer(debug);
     var instance = instantiate(buffer);
     assertEquals(11, instance.exports.blarg());
 })();
 
 (function ImportTest() {
     let builder = new WasmModuleBuilder();
-    var index = builder.addImport("print", makeSig_v_x(kAstI32));
+  var index = builder.addImport("", "print", makeSig_v_x(kAstI32));
     builder.addFunction("foo", kSig_v_v)
         .addBody([kExprI8Const, 13, kExprCallFunction, index])
         .exportAs("main");
 
     var buffer = builder.toBuffer(debug);
-    var instance = instantiate(buffer, {print: print});
+    var instance = instantiate(buffer, {"": {print: print}});
     print("should print 13! ");
     instance.exports.main();
 })();
 
 (function LocalsTest() {
     let builder = new WasmModuleBuilder();
     builder.addFunction(undefined, kSig_i_i)
         .addLocals({i32_count: 1})
         .addBody([kExprGetLocal, 0, kExprSetLocal, 1, kExprGetLocal, 1])
         .exportAs("main");
@@ skipping 91 matching lines @@
     var array2 = new Uint8Array(buffer2, kPad, buffer.byteLength);
     for (var i = 0; i < array2.byteLength; i++) {
       array2[i] = array[i];
     }
     var instance = instantiate(array2);
     assertEquals(17, instance.exports.blarg());
 })();
 
 (function ImportTestTwoLevel() {
     let builder = new WasmModuleBuilder();
-    var index = builder.addImportWithModule("mod", "print", makeSig_v_x(kAstI32));
+    var index = builder.addImport("mod", "print", makeSig_v_x(kAstI32));
     builder.addFunction("foo", kSig_v_v)
         .addBody([kExprI8Const, 19, kExprCallFunction, index])
         .exportAs("main");
 
     var buffer = builder.toBuffer(debug);
     var instance = instantiate(buffer, {mod: {print: print}});
     print("should print 19! ");
     instance.exports.main();
 })();