Move completion_queue.cc to common
diff --git a/Makefile b/Makefile
index 3b0e452..81345e0 100644
--- a/Makefile
+++ b/Makefile
@@ -2154,11 +2154,11 @@
     src/cpp/client/create_channel.cc \
     src/cpp/client/credentials.cc \
     src/cpp/client/internal_stub.cc \
+    src/cpp/common/completion_queue.cc \
     src/cpp/common/rpc_method.cc \
     src/cpp/proto/proto_utils.cc \
     src/cpp/server/async_server.cc \
     src/cpp/server/async_server_context.cc \
-    src/cpp/server/completion_queue.cc \
     src/cpp/server/server.cc \
     src/cpp/server/server_builder.cc \
     src/cpp/server/server_context_impl.cc \
@@ -2213,11 +2213,11 @@
 src/cpp/client/create_channel.cc: $(OPENSSL_DEP)
 src/cpp/client/credentials.cc: $(OPENSSL_DEP)
 src/cpp/client/internal_stub.cc: $(OPENSSL_DEP)
+src/cpp/common/completion_queue.cc: $(OPENSSL_DEP)
 src/cpp/common/rpc_method.cc: $(OPENSSL_DEP)
 src/cpp/proto/proto_utils.cc: $(OPENSSL_DEP)
 src/cpp/server/async_server.cc: $(OPENSSL_DEP)
 src/cpp/server/async_server_context.cc: $(OPENSSL_DEP)
-src/cpp/server/completion_queue.cc: $(OPENSSL_DEP)
 src/cpp/server/server.cc: $(OPENSSL_DEP)
 src/cpp/server/server_builder.cc: $(OPENSSL_DEP)
 src/cpp/server/server_context_impl.cc: $(OPENSSL_DEP)
@@ -2273,11 +2273,11 @@
 objs/$(CONFIG)/src/cpp/client/create_channel.o: 
 objs/$(CONFIG)/src/cpp/client/credentials.o: 
 objs/$(CONFIG)/src/cpp/client/internal_stub.o: 
+objs/$(CONFIG)/src/cpp/common/completion_queue.o: 
 objs/$(CONFIG)/src/cpp/common/rpc_method.o: 
 objs/$(CONFIG)/src/cpp/proto/proto_utils.o: 
 objs/$(CONFIG)/src/cpp/server/async_server.o: 
 objs/$(CONFIG)/src/cpp/server/async_server_context.o: 
-objs/$(CONFIG)/src/cpp/server/completion_queue.o: 
 objs/$(CONFIG)/src/cpp/server/server.o: 
 objs/$(CONFIG)/src/cpp/server/server_builder.o: 
 objs/$(CONFIG)/src/cpp/server/server_context_impl.o: 
diff --git a/build.json b/build.json
index 020a756..28039db 100644
--- a/build.json
+++ b/build.json
@@ -411,11 +411,11 @@
         "src/cpp/client/create_channel.cc",
         "src/cpp/client/credentials.cc",
         "src/cpp/client/internal_stub.cc",
+        "src/cpp/common/completion_queue.cc",
         "src/cpp/common/rpc_method.cc",
         "src/cpp/proto/proto_utils.cc",
         "src/cpp/server/async_server.cc",
         "src/cpp/server/async_server_context.cc",
-        "src/cpp/server/completion_queue.cc",
         "src/cpp/server/server.cc",
         "src/cpp/server/server_builder.cc",
         "src/cpp/server/server_context_impl.cc",
diff --git a/src/cpp/server/completion_queue.cc b/src/cpp/common/completion_queue.cc
similarity index 100%
rename from src/cpp/server/completion_queue.cc
rename to src/cpp/common/completion_queue.cc