[mojo] Add typemap and variant support to generators

mojo/public/interfaces/bindings/tests/BUILD.gn

Index: mojo/public/interfaces/bindings/tests/BUILD.gn
diff --git a/mojo/public/interfaces/bindings/tests/BUILD.gn b/mojo/public/interfaces/bindings/tests/BUILD.gn
index 802bd5803dfd62514ba323afb6f2bd98642f62b2..d0af97059b2921a52c39e29b79f9ea63fd482c8d 100644
--- a/mojo/public/interfaces/bindings/tests/BUILD.gn
+++ b/mojo/public/interfaces/bindings/tests/BUILD.gn
@@ -68,3 +68,37 @@ mojom("versioning_test_client_interfaces") {
 
   with_environment = false
 }
+
+mojom("test_interfaces_chromium") {
+  testonly = true
+
+  sources = [
+    "test_native_types.mojom",
+  ]
+
+  variant = "chromium"
+  typemaps = [ "chromium_test.typemap" ]
+
+  with_environment = false
+
+  public_deps = [
+    ":test_interfaces",
+  ]
+}
+
+mojom("test_interfaces_blink") {
+  testonly = true
+
+  sources = [
+    "test_native_types.mojom",
+  ]
+
+  variant = "blink"
+  typemaps = [ "blink_test.typemap" ]
+
+  with_environment = false
+
+  public_deps = [
+    ":test_interfaces",
+  ]
+}