Mojo JS Bindings: add support for associative arrays (Mojo map type)

mojo/public/interfaces/bindings/tests/test_structs.mojom

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import "mojo/public/interfaces/bindings/tests/rect.mojom"
 
 [JavaPackage="org.chromium.mojo.bindings.test.mojom.test_structs"]
 module mojo.test {
 
 struct NamedRegion {
@@ skipping 90 matching lines @@
   const int32 TEN_TOO = EType.E2;
   EType f0 = E0; // 0
   EType f1 = E1; // 1
   EType f2 = E2; // 10
   EType f3 = E3; // 10
   EType f4 = E4; // 11
   int32 f5 = TEN;
   int32 f6 = ALSO_TEN;
 };
 
-}
+// Used to verify that all possible Map key field types can be encoded and
+// decoded successfully.
+
+struct MapKeyTypes {
+  map<bool, bool> f0;
+  map<int8, int8> f1;
+  map<uint8, uint8> f2;
+  map<int16, int16> f3;
+  map<uint16, uint16> f4;
+  map<int32, int32> f5;
+  map<uint32, uint32> f6;
+  map<int64, int64> f7;
+  map<uint64, uint64> f8;
+  map<float, float> f9;
+  map<double, double> f10;
+  map<string, string> f11;
+};
+
+// Used to verify that some common value types can be encoded and decoded
+// successfully.
+
+struct MapValueTypes {
+  map<string, array<string>> f0;
+  map<string, array<string>?> f1;
+  map<string, array<string?>> f2;
+};
+
+}