Remove usages of "whitelist" in Firestore.

Fixes #6755.

Author: wilhuff

Firestore/core/src/remote/datastore.cc

@@ -83,7 +83,7 @@ void LogGrpcCallFinished(absl::string_view rpc_name,
   if (LogIsDebugEnabled()) {
     auto headers =
         Datastore::GetWhitelistedHeadersAsString(call->GetResponseHeaders());
-    LOG_DEBUG("RPC %s returned headers (whitelisted): %s", rpc_name, headers);
+    LOG_DEBUG("RPC %s returned headers (allowlisted): %s", rpc_name, headers);
   }
 }
 
@@ -334,13 +334,13 @@ bool Datastore::IsPermanentWriteError(const Status& error) {
 
 std::string Datastore::GetWhitelistedHeadersAsString(
     const GrpcCall::Metadata& headers) {
-  static std::unordered_set<std::string> whitelist = {
+  static std::unordered_set<std::string> allowlist = {
       "date", "x-google-backends", "x-google-netmon-label", "x-google-service",
       "x-google-gfe-request-trace"};
 
   std::string result;
   for (const auto& kv : headers) {
-    if (whitelist.find(MakeString(kv.first)) != whitelist.end()) {
+    if (allowlist.find(MakeString(kv.first)) != allowlist.end()) {
       absl::StrAppend(&result, MakeStringView(kv.first), ": ",
                       MakeStringView(kv.second), "\n");
     }

Firestore/core/src/remote/stream.cc

@@ -202,7 +202,7 @@ void Stream::OnStreamRead(const grpc::ByteBuffer& message) {
   HARD_ASSERT(IsStarted(), "OnStreamRead called for a stopped stream.");
 
   if (LogIsDebugEnabled()) {
-    LOG_DEBUG("%s headers (whitelisted): %s", GetDebugDescription(),
+    LOG_DEBUG("%s headers (allowlisted): %s", GetDebugDescription(),
               Datastore::GetWhitelistedHeadersAsString(
                   grpc_stream_->GetResponseHeaders()));
   }

Firestore/core/test/unit/remote/datastore_test.cc

@@ -180,7 +180,7 @@ TEST_F(DatastoreTest, WhitelistedHeaders) {
   GrpcStream::Metadata headers = {
       {"date", "date value"},
       {"x-google-backends", "backend value"},
-      {"x-google-foo", "should not be in result"},  // Not whitelisted
+      {"x-google-foo", "should not be in result"},  // Not allowlisted
       {"x-google-gfe-request-trace", "request trace"},
       {"x-google-netmon-label", "netmon label"},
       {"x-google-service", "service 1"},