Adapt BindableService in ServerBuilder#addService

Makes binding services to server as simple as it can get.
diff --git a/compiler/src/java_plugin/cpp/java_generator.cpp b/compiler/src/java_plugin/cpp/java_generator.cpp
index fc8f472..81e452d 100644
--- a/compiler/src/java_plugin/cpp/java_generator.cpp
+++ b/compiler/src/java_plugin/cpp/java_generator.cpp
@@ -776,7 +776,7 @@
   vars["MethodType"] = "io.grpc.MethodDescriptor.MethodType";
   vars["ServerMethodDefinition"] =
       "io.grpc.ServerMethodDefinition";
-  vars["BindableService"] = "io.grpc.stub.BindableService";
+  vars["BindableService"] = "io.grpc.BindableService";
   vars["ServerServiceDefinition"] =
       "io.grpc.ServerServiceDefinition";
   vars["AbstractStub"] = "io.grpc.stub.AbstractStub";
diff --git a/compiler/src/test/golden/TestService.java.txt b/compiler/src/test/golden/TestService.java.txt
index 4f19fde..b029819 100644
--- a/compiler/src/test/golden/TestService.java.txt
+++ b/compiler/src/test/golden/TestService.java.txt
@@ -224,7 +224,7 @@
     }
   }
 
-  public static abstract class AbstractTestService implements TestService, io.grpc.stub.BindableService {
+  public static abstract class AbstractTestService implements TestService, io.grpc.BindableService {
     @Override public io.grpc.ServerServiceDefinition bindService() {
       return TestServiceGrpc.bindService(this);
     }
diff --git a/compiler/src/testLite/golden/TestService.java.txt b/compiler/src/testLite/golden/TestService.java.txt
index da72d6f..726bf70 100644
--- a/compiler/src/testLite/golden/TestService.java.txt
+++ b/compiler/src/testLite/golden/TestService.java.txt
@@ -224,7 +224,7 @@
     }
   }
 
-  public static abstract class AbstractTestService implements TestService, io.grpc.stub.BindableService {
+  public static abstract class AbstractTestService implements TestService, io.grpc.BindableService {
     @Override public io.grpc.ServerServiceDefinition bindService() {
       return TestServiceGrpc.bindService(this);
     }
diff --git a/compiler/src/testNano/golden/TestService.java.txt b/compiler/src/testNano/golden/TestService.java.txt
index 3aacbf8..0be68b1 100644
--- a/compiler/src/testNano/golden/TestService.java.txt
+++ b/compiler/src/testNano/golden/TestService.java.txt
@@ -302,7 +302,7 @@
     }
   }
 
-  public static abstract class AbstractTestService implements TestService, io.grpc.stub.BindableService {
+  public static abstract class AbstractTestService implements TestService, io.grpc.BindableService {
     @Override public io.grpc.ServerServiceDefinition bindService() {
       return TestServiceGrpc.bindService(this);
     }