Update mojo sdk to rev e7270700d671fa8e458b4d8c9e47f7bcfb65da0b

third_party/mojo/src/mojo/public/tools/bindings/generators/mojom_cpp_generator.py

Index: third_party/mojo/src/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
diff --git a/third_party/mojo/src/mojo/public/tools/bindings/generators/mojom_cpp_generator.py b/third_party/mojo/src/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
index 10ce58214599a330c56e6b52e35ea5fb18cb9331..b5bf6a460ee00c54a435f4840d94d0026dfb4611 100644
--- a/third_party/mojo/src/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
+++ b/third_party/mojo/src/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
@@ -227,6 +227,12 @@ def GetCppFieldType(kind):
     return "mojo::internal::StringPointer"
   return _kind_to_cpp_type[kind]
 
+def GetUnionGetterReturnType(kind):
+  if (mojom.IsStructKind(kind) or mojom.IsArrayKind(kind) or
+      mojom.IsMapKind(kind)):
+    return "%s&" % GetCppWrapperType(kind)
+  return GetCppResultWrapperType(kind)
+
 def IsStructWithHandles(struct):
   for pf in struct.packed.packed_fields:
     if mojom.IsAnyHandleKind(pf.field.kind):
@@ -335,6 +341,7 @@ class Generator(generator.Generator):
     "cpp_pod_type": GetCppPodType,
     "cpp_result_type": GetCppResultWrapperType,
     "cpp_type": GetCppType,
+    "cpp_union_getter_return_type": GetUnionGetterReturnType,
     "cpp_wrapper_type": GetCppWrapperType,
     "default_value": DefaultValue,
     "expression_to_text": ExpressionToText,
@@ -374,7 +381,7 @@ class Generator(generator.Generator):
       "kinds": self.module.kinds,
       "enums": self.module.enums,
       "structs": self.GetStructs(),
-      "unions": self.module.unions,
+      "unions": self.GetUnions(),
       "interfaces": self.GetInterfaces(),
     }