Fix compilation under Visual Studio (#2288)

VS2017 complains that enumeration numbers are not valid targets of a
using declaration outside class scope.

Firestore/core/test/firebase/firestore/remote/grpc_stream_test.cc

@@ -42,6 +42,7 @@ namespace remote {
 using util::AsyncQueue;
 using util::ByteBufferToString;
 using util::CompletionEndState;
+using util::CompletionResult;
 using util::CreateNoOpConnectivityMonitor;
 using util::ExecutorStd;
 using util::GetFirestoreErrorCodeName;
@@ -50,8 +51,6 @@ using util::GrpcStreamTester;
 using util::MakeByteBuffer;
 using util::Status;
 using util::StringFormat;
-using util::CompletionResult::Error;
-using util::CompletionResult::Ok;
 using Type = GrpcCompletion::Type;
 
 namespace {
@@ -270,7 +269,7 @@ TEST_F(GrpcStreamTest, ObserverReceivesOnStart) {
 TEST_F(GrpcStreamTest, ObserverReceivesOnError) {
   worker_queue.EnqueueBlocking([&] { stream->Start(); });
 
-  ForceFinish({{Type::Read, Error},
+  ForceFinish({{Type::Read, CompletionResult::Error},
                {Type::Finish, grpc::Status{grpc::RESOURCE_EXHAUSTED, ""}}});
 
   EXPECT_EQ(observed_states(),
@@ -426,9 +425,9 @@ TEST_F(GrpcStreamTest, ObserverCanImmediatelyDestroyStreamOnError) {
 
   worker_queue.EnqueueBlocking([&] { stream->Start(); });
 
-  ForceFinish({{Type::Read, Error}});
+  ForceFinish({{Type::Read, CompletionResult::Error}});
   EXPECT_NE(stream, nullptr);
-  EXPECT_NO_THROW(ForceFinish({{Type::Finish, Ok}}));
+  EXPECT_NO_THROW(ForceFinish({{Type::Finish, CompletionResult::Ok}}));
   EXPECT_EQ(stream, nullptr);
 }
 
@@ -453,7 +452,7 @@ TEST_F(GrpcStreamTest, ObserverCanImmediatelyDestroyStreamOnFinishAndNotify) {
 TEST_F(GrpcStreamTest, DoubleFinish_FailThenFinishImmediately) {
   worker_queue.EnqueueBlocking([&] { stream->Start(); });
 
-  ForceFinish({{Type::Read, Error}});
+  ForceFinish({{Type::Read, CompletionResult::Error}});
   KeepPollingGrpcQueue();
   worker_queue.EnqueueBlocking(
       [&] { EXPECT_NO_THROW(stream->FinishImmediately()); });
@@ -462,7 +461,7 @@ TEST_F(GrpcStreamTest, DoubleFinish_FailThenFinishImmediately) {
 TEST_F(GrpcStreamTest, DoubleFinish_FailThenWriteAndFinish) {
   worker_queue.EnqueueBlocking([&] { stream->Start(); });
 
-  ForceFinish({{Type::Read, Error}});
+  ForceFinish({{Type::Read, CompletionResult::Error}});
   KeepPollingGrpcQueue();
   worker_queue.EnqueueBlocking(
       [&] { EXPECT_NO_THROW(stream->WriteAndFinish({})); });
@@ -493,7 +492,7 @@ TEST_F(GrpcStreamTest, DoubleFinish_FailThenFailAgain) {
   // Normally, "Finish" never fails, but for the test it's easier to abuse the
   // finish operation that has already been enqueued by `OnOperationFailed`
   // rather than adding a new operation.
-  ForceFinish({{Type::Finish, Error}});
+  ForceFinish({{Type::Finish, CompletionResult::Error}});
 }
 
 }  // namespace remote

Firestore/core/test/firebase/firestore/remote/grpc_streaming_reader_test.cc

@@ -34,6 +34,7 @@ namespace remote {
 using util::AsyncQueue;
 using util::ByteBufferToString;
 using util::CompletionEndState;
+using util::CompletionResult;
 using util::CreateNoOpConnectivityMonitor;
 using util::ExecutorStd;
 using util::GetFirestoreErrorCodeName;
@@ -43,8 +44,6 @@ using util::MakeByteBuffer;
 using util::Status;
 using util::StatusOr;
 using util::StringFormat;
-using util::CompletionResult::Error;
-using util::CompletionResult::Ok;
 using Type = GrpcCompletion::Type;
 
 class GrpcStreamingReaderTest : public testing::Test {
@@ -153,9 +152,9 @@ TEST_F(GrpcStreamingReaderTest, OneSuccessfulRead) {
   StartReader();
 
   ForceFinishAnyTypeOrder({
-      {Type::Write, Ok},
+      {Type::Write, CompletionResult::Ok},
       {Type::Read, MakeByteBuffer("foo")},
-      /*Read after last*/ {Type::Read, Error},
+      /*Read after last*/ {Type::Read, CompletionResult::Error},
   });
 
   EXPECT_FALSE(status.has_value());
@@ -172,10 +171,10 @@ TEST_F(GrpcStreamingReaderTest, TwoSuccessfulReads) {
   StartReader();
 
   ForceFinishAnyTypeOrder({
-      {Type::Write, Ok},
+      {Type::Write, CompletionResult::Ok},
       {Type::Read, MakeByteBuffer("foo")},
       {Type::Read, MakeByteBuffer("bar")},
-      /*Read after last*/ {Type::Read, Error},
+      /*Read after last*/ {Type::Read, CompletionResult::Error},
   });
   EXPECT_FALSE(status.has_value());
 
@@ -191,7 +190,8 @@ TEST_F(GrpcStreamingReaderTest, TwoSuccessfulReads) {
 TEST_F(GrpcStreamingReaderTest, FinishWhileReading) {
   StartReader();
 
-  ForceFinishAnyTypeOrder({{Type::Write, Ok}, {Type::Read, Ok}});
+  ForceFinishAnyTypeOrder({{Type::Write, CompletionResult::Ok},
+                           {Type::Read, CompletionResult::Ok}});
   EXPECT_FALSE(status.has_value());
 
   KeepPollingGrpcQueue();
@@ -243,8 +243,8 @@ TEST_F(GrpcStreamingReaderTest, ErrorOnFirstRead) {
   StartReader();
 
   ForceFinishAnyTypeOrder({
-      {Type::Write, Ok},
-      {Type::Read, Error},
+      {Type::Write, CompletionResult::Ok},
+      {Type::Read, CompletionResult::Error},
   });
 
   ForceFinish(
@@ -258,9 +258,9 @@ TEST_F(GrpcStreamingReaderTest, ErrorOnSecondRead) {
   StartReader();
 
   ForceFinishAnyTypeOrder({
-      {Type::Write, Ok},
-      {Type::Read, Ok},
-      {Type::Read, Error},
+      {Type::Write, CompletionResult::Ok},
+      {Type::Read, CompletionResult::Ok},
+      {Type::Read, CompletionResult::Error},
   });
 
   ForceFinish({{Type::Finish, grpc::Status{grpc::StatusCode::DATA_LOSS, ""}}});
@@ -279,9 +279,9 @@ TEST_F(GrpcStreamingReaderTest, CallbackCanDestroyReaderOnSuccess) {
   });
 
   ForceFinishAnyTypeOrder({
-      {Type::Write, Ok},
+      {Type::Write, CompletionResult::Ok},
       {Type::Read, MakeByteBuffer("foo")},
-      /*Read after last*/ {Type::Read, Error},
+      /*Read after last*/ {Type::Read, CompletionResult::Error},
   });
 
   EXPECT_NE(reader, nullptr);
@@ -297,8 +297,8 @@ TEST_F(GrpcStreamingReaderTest, CallbackCanDestroyReaderOnError) {
   });
 
   ForceFinishAnyTypeOrder({
-      {Type::Write, Ok},
-      {Type::Read, Error},
+      {Type::Write, CompletionResult::Ok},
+      {Type::Read, CompletionResult::Error},
   });
 
   grpc::Status error_status{grpc::StatusCode::DATA_LOSS, ""};

Firestore/core/test/firebase/firestore/remote/grpc_unary_call_test.cc

@@ -36,14 +36,13 @@ namespace remote {
 using util::AsyncQueue;
 using util::ByteBufferToString;
 using util::CompletionEndState;
+using util::CompletionResult;
 using util::CreateNoOpConnectivityMonitor;
 using util::ExecutorStd;
 using util::GrpcStreamTester;
 using util::MakeByteBuffer;
 using util::Status;
 using util::StatusOr;
-using util::CompletionResult::Error;
-using util::CompletionResult::Ok;
 using Type = GrpcCompletion::Type;
 
 class GrpcUnaryCallTest : public testing::Test {
@@ -133,7 +132,7 @@ TEST_F(GrpcUnaryCallDeathTest, CannotStartTwice) {
 
 TEST_F(GrpcUnaryCallDeathTest, CannotRestart) {
   StartCall();
-  ForceFinish({{Type::Finish, Ok}});
+  ForceFinish({{Type::Finish, CompletionResult::Ok}});
   EXPECT_DEATH_IF_SUPPORTED(StartCall(), "");
 }