Update mojo sdk to rev 1027d24a1f68c6d10b7539b32114f1272b2cc9f1

third_party/mojo/src/mojo/public/cpp/bindings/lib/callback_internal.h

Index: third_party/mojo/src/mojo/public/cpp/bindings/lib/callback_internal.h
diff --git a/third_party/mojo/src/mojo/public/cpp/bindings/lib/callback_internal.h b/third_party/mojo/src/mojo/public/cpp/bindings/lib/callback_internal.h
index f76ebef59e6c67ba12b4f13e67534be49cc3cdb7..9df5b40a73555e7f72aa8ac046a62aefd1701058 100644
--- a/third_party/mojo/src/mojo/public/cpp/bindings/lib/callback_internal.h
+++ b/third_party/mojo/src/mojo/public/cpp/bindings/lib/callback_internal.h
@@ -5,6 +5,8 @@
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_CALLBACK_INTERNAL_H_
 
+#include "mojo/public/cpp/bindings/lib/template_util.h"
+
 namespace mojo {
 class String;
 
@@ -20,6 +22,31 @@ struct Callback_ParamTraits<String> {
   typedef const String& ForwardType;
 };
 
+template <typename T, typename... Args>
+struct HasCompatibleCallOperator {
+  // This template's second parameter is the signature of the operator()
+  // overload we want to try to detect:
+  //   void operator()(Args...) const;
+  template <typename U,
+            void (U::*)(
+                typename internal::Callback_ParamTraits<Args>::ForwardType...)
+                const>
+  struct TestType {};
+
+  // This matches type U if it has a call operator with the
+  // expected signature.
+  template <typename U>
+  static YesType Test(TestType<U, &U::operator()>*);
+
+  // This matches anything else.
+  template <typename U>
+  static NoType Test(...);
+
+  // HasCompatibleCallOperator<T, Args...>::value will be true if T has a
+  // compatible call operator.
+  enum { value = (sizeof(Test<T>(nullptr)) == sizeof(YesType)) };
+};
+
 }  // namespace internal
 }  // namespace mojo