Mojo C++ bindings: introduce mojo::WTFMap for blink bindings.

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.
 
 [JavaPackage="org.chromium.mojo.bindings.test.mojom.test_structs"]
 module mojo.test;
 
 import "mojo/public/interfaces/bindings/tests/rect.mojom";
 
 struct NamedRegion {
@@ skipping 95 matching lines @@
   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;
+  // TODO(yzshen): WTF::HashMap doesn't support bool as key.
+  // 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;
@@ skipping 243 matching lines @@
 
 struct ContainsOther {
   int32 other;
 };
 
 // Used to verify that structs can contain interface requests.
 
 struct ContainsInterfaceRequest {
   SomeInterface& request;
 };