Remove ChannelInterface and replace it with Channel
diff --git a/test/cpp/qps/client.h b/test/cpp/qps/client.h
index 1c4f463..5395d02 100644
--- a/test/cpp/qps/client.h
+++ b/test/cpp/qps/client.h
@@ -125,11 +125,11 @@
       channel_ = CreateTestChannel(target, config.enable_ssl());
       stub_ = TestService::NewStub(channel_);
     }
-    ChannelInterface* get_channel() { return channel_.get(); }
+    Channel* get_channel() { return channel_.get(); }
     TestService::Stub* get_stub() { return stub_.get(); }
 
    private:
-    std::shared_ptr<ChannelInterface> channel_;
+    std::shared_ptr<Channel> channel_;
     std::unique_ptr<TestService::Stub> stub_;
   };
   std::vector<ClientChannelInfo> channels_;
diff --git a/test/cpp/qps/perf_db_client.h b/test/cpp/qps/perf_db_client.h
index 7a9d86d..3433cd8 100644
--- a/test/cpp/qps/perf_db_client.h
+++ b/test/cpp/qps/perf_db_client.h
@@ -38,7 +38,7 @@
 
 #include <grpc/grpc.h>
 #include <grpc++/channel_arguments.h>
-#include <grpc++/channel_interface.h>
+#include <grpc++/channel.h>
 #include <grpc++/client_context.h>
 #include <grpc++/create_channel.h>
 #include <grpc++/credentials.h>
@@ -65,7 +65,7 @@
     client_user_time_ = DBL_MIN;
   }
 
-  void init(std::shared_ptr<ChannelInterface> channel) {
+  void init(std::shared_ptr<Channel> channel) {
     stub_ = PerfDbTransfer::NewStub(channel);
   }