Prevent cm from incrementing 0.

The kernel will return an error now when the context
manager tries to increment the 0 handle.

Bug: 166779391
Test: binderLibTest
Change-Id: Iab7af80b491c49c37425e840432d9071f9f36ff4
diff --git a/libs/binder/tests/binderLibTest.cpp b/libs/binder/tests/binderLibTest.cpp
index a0f12cf..18a9f86 100644
--- a/libs/binder/tests/binderLibTest.cpp
+++ b/libs/binder/tests/binderLibTest.cpp
@@ -447,6 +447,12 @@
     EXPECT_DEATH({ ProcessState::self(); }, "libbinder ProcessState can not be used after fork");
 }
 
+TEST_F(BinderLibTest, AddManagerToManager) {
+    sp<IServiceManager> sm = defaultServiceManager();
+    sp<IBinder> binder = IInterface::asBinder(sm);
+    EXPECT_EQ(NO_ERROR, sm->addService(String16("binderLibTest-manager"), binder));
+}
+
 TEST_F(BinderLibTest, WasParceled) {
     auto binder = sp<BBinder>::make();
     EXPECT_FALSE(binder->wasParceled());