Mojo C++ bindings: remove the lock in MultiplexRouter if it only serves a single interface.

mojo/public/cpp/bindings/tests/multiplex_router_unittest.cc

Index: mojo/public/cpp/bindings/tests/multiplex_router_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/multiplex_router_unittest.cc b/mojo/public/cpp/bindings/tests/multiplex_router_unittest.cc
index b236d0a7b99ac18367ae7d5112b8896eb4a825ea..0db42db25fc7e4f5a0c78ae02a8a4d31f9bc62a2 100644
--- a/mojo/public/cpp/bindings/tests/multiplex_router_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/multiplex_router_unittest.cc
@@ -31,9 +31,11 @@ class MultiplexRouterTest : public testing::Test {
 
   void SetUp() override {
     MessagePipe pipe;
-    router0_ = new MultiplexRouter(true, std::move(pipe.handle0),
+    router0_ = new MultiplexRouter(std::move(pipe.handle0),
+                                   MultiplexRouter::MULTI_INTERFACE, false,
                                    base::ThreadTaskRunnerHandle::Get());
-    router1_ = new MultiplexRouter(true, std::move(pipe.handle1),
+    router1_ = new MultiplexRouter(std::move(pipe.handle1),
+                                   MultiplexRouter::MULTI_INTERFACE, true,
                                    base::ThreadTaskRunnerHandle::Get());
     router0_->CreateEndpointHandlePair(&endpoint0_, &endpoint1_);
     endpoint1_ =