Revert "dcsctp: Add per-stream-limit, refactor limits."

This reverts commit 4c990e2e56157175324e651f95f3d8c6a0e5c030.

Reason for revert: Breaks downstream build.

Original change's description:
> dcsctp: Add per-stream-limit, refactor limits.
>
> The limits have been moved out from the Send Queue as they were enforced
> outside the queue anyway (in the socket). That was a preparation for
> adding even more limits; There is now also a per-stream limit, allowing
> individual streams to have one (global) limit, and the entire socket to
> have another limit.
>
> These limits are very small in the default options. In Chrome, the limit
> is 16MB per stream, so expect the defaults to be updated when the
> additional buffering outside dcSCTP is removed.
>
> Bug: chromium:41221056
> Change-Id: I9f835be05d349cbfce3e9235d34b5ea0e2fe87d1
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/342481
> Reviewed-by: Florent Castelli <orphis@webrtc.org>
> Commit-Queue: Victor Boivie <boivie@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#41895}

Bug: chromium:41221056
Change-Id: Icd57fbfca87d6b512cfc7f7682ae709000c2bcad
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/343080
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Reviewed-by: Victor Boivie <boivie@webrtc.org>
Bot-Commit: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#41901}
diff --git a/net/dcsctp/public/dcsctp_options.h b/net/dcsctp/public/dcsctp_options.h
index 6a6a8cd..600e8a3 100644
--- a/net/dcsctp/public/dcsctp_options.h
+++ b/net/dcsctp/public/dcsctp_options.h
@@ -85,13 +85,9 @@
   // buffer is fully utilized.
   size_t max_receiver_window_buffer_size = 5 * 1024 * 1024;
 
-  // Send queue total size limit. It will not be possible to queue more data if
-  // the queue size is larger than this number.
-  size_t total_send_queue_limit = 2'000'000;
-
-  // Per stream send queue size limit. Similar to `total_send_queue_limit`, but
-  // limiting the size of individual streams.
-  size_t per_stream_send_queue_limit = 2'000'000;
+  // Maximum send buffer size. It will not be possible to queue more data than
+  // this before sending it.
+  size_t max_send_buffer_size = 2'000'000;
 
   // A threshold that, when the amount of data in the send buffer goes below
   // this value, will trigger `DcSctpCallbacks::OnTotalBufferedAmountLow`.
diff --git a/net/dcsctp/socket/dcsctp_socket.cc b/net/dcsctp/socket/dcsctp_socket.cc
index c92ec37..0667e6f 100644
--- a/net/dcsctp/socket/dcsctp_socket.cc
+++ b/net/dcsctp/socket/dcsctp_socket.cc
@@ -215,6 +215,7 @@
                      absl::bind_front(&DcSctpSocket::OnSentPacket, this)),
       send_queue_(log_prefix_,
                   &callbacks_,
+                  options_.max_send_buffer_size,
                   options_.mtu,
                   options_.default_stream_priority,
                   options_.total_buffered_amount_low_threshold) {}
@@ -543,9 +544,7 @@
                        "Unable to send message as the socket is shutting down");
     return SendStatus::kErrorShuttingDown;
   }
-  if (send_queue_.total_buffered_amount() >= options_.total_send_queue_limit ||
-      send_queue_.buffered_amount(message.stream_id()) >=
-          options_.per_stream_send_queue_limit) {
+  if (send_queue_.IsFull()) {
     if (lifecycle_id.IsSet()) {
       callbacks_.OnLifecycleEnd(lifecycle_id);
     }
diff --git a/net/dcsctp/socket/dcsctp_socket_test.cc b/net/dcsctp/socket/dcsctp_socket_test.cc
index d64774b..dfe8ba6 100644
--- a/net/dcsctp/socket/dcsctp_socket_test.cc
+++ b/net/dcsctp/socket/dcsctp_socket_test.cc
@@ -1694,37 +1694,6 @@
   MaybeHandoverSocketAndSendMessage(a, std::move(z));
 }
 
-TEST(DcSctpSocketTest, RespectsPerStreamQueueLimit) {
-  DcSctpOptions options = {.total_send_queue_limit = 4000,
-                           .per_stream_send_queue_limit = 1000};
-  SocketUnderTest a("A", options);
-  EXPECT_EQ(a.socket.Send(
-                DcSctpMessage(StreamID(1), PPID(53), std::vector<uint8_t>(600)),
-                kSendOptions),
-            SendStatus::kSuccess);
-  EXPECT_EQ(a.socket.Send(
-                DcSctpMessage(StreamID(1), PPID(53), std::vector<uint8_t>(600)),
-                kSendOptions),
-            SendStatus::kSuccess);
-  EXPECT_EQ(a.socket.Send(
-                DcSctpMessage(StreamID(1), PPID(53), std::vector<uint8_t>(600)),
-                kSendOptions),
-            SendStatus::kErrorResourceExhaustion);
-  // The per-stream limit for SID=1 is reached, but not SID=2.
-  EXPECT_EQ(a.socket.Send(
-                DcSctpMessage(StreamID(2), PPID(53), std::vector<uint8_t>(600)),
-                kSendOptions),
-            SendStatus::kSuccess);
-  EXPECT_EQ(a.socket.Send(
-                DcSctpMessage(StreamID(2), PPID(53), std::vector<uint8_t>(600)),
-                kSendOptions),
-            SendStatus::kSuccess);
-  EXPECT_EQ(a.socket.Send(
-                DcSctpMessage(StreamID(2), PPID(53), std::vector<uint8_t>(600)),
-                kSendOptions),
-            SendStatus::kErrorResourceExhaustion);
-}
-
 TEST_P(DcSctpSocketParametrizedTest, HasReasonableBufferedAmountValues) {
   SocketUnderTest a("A");
   auto z = std::make_unique<SocketUnderTest>("Z");
diff --git a/net/dcsctp/tx/rr_send_queue.cc b/net/dcsctp/tx/rr_send_queue.cc
index 2193880..3e682fd 100644
--- a/net/dcsctp/tx/rr_send_queue.cc
+++ b/net/dcsctp/tx/rr_send_queue.cc
@@ -35,11 +35,13 @@
 
 RRSendQueue::RRSendQueue(absl::string_view log_prefix,
                          DcSctpSocketCallbacks* callbacks,
+                         size_t buffer_size,
                          size_t mtu,
                          StreamPriority default_priority,
                          size_t total_buffered_amount_low_threshold)
     : log_prefix_(log_prefix),
       callbacks_(*callbacks),
+      buffer_size_(buffer_size),
       default_priority_(default_priority),
       scheduler_(log_prefix_, mtu),
       total_buffered_amount_(
@@ -377,6 +379,10 @@
   RTC_DCHECK(IsConsistent());
 }
 
+bool RRSendQueue::IsFull() const {
+  return total_buffered_amount() >= buffer_size_;
+}
+
 bool RRSendQueue::IsEmpty() const {
   return total_buffered_amount() == 0;
 }
diff --git a/net/dcsctp/tx/rr_send_queue.h b/net/dcsctp/tx/rr_send_queue.h
index 1a370a2..b6c359d 100644
--- a/net/dcsctp/tx/rr_send_queue.h
+++ b/net/dcsctp/tx/rr_send_queue.h
@@ -56,6 +56,7 @@
  public:
   RRSendQueue(absl::string_view log_prefix,
               DcSctpSocketCallbacks* callbacks,
+              size_t buffer_size,
               size_t mtu,
               StreamPriority default_priority,
               size_t total_buffered_amount_low_threshold);
@@ -270,6 +271,7 @@
 
   const absl::string_view log_prefix_;
   DcSctpSocketCallbacks& callbacks_;
+  const size_t buffer_size_;
   const StreamPriority default_priority_;
   OutgoingMessageId current_message_id = OutgoingMessageId(0);
   StreamScheduler scheduler_;
diff --git a/net/dcsctp/tx/rr_send_queue_test.cc b/net/dcsctp/tx/rr_send_queue_test.cc
index 9beba95..632cd8f 100644
--- a/net/dcsctp/tx/rr_send_queue_test.cc
+++ b/net/dcsctp/tx/rr_send_queue_test.cc
@@ -35,6 +35,7 @@
 constexpr Timestamp kNow = Timestamp::Zero();
 constexpr StreamID kStreamID(1);
 constexpr PPID kPPID(53);
+constexpr size_t kMaxQueueSize = 1000;
 constexpr StreamPriority kDefaultPriority(10);
 constexpr size_t kBufferedAmountLowThreshold = 500;
 constexpr size_t kOneFragmentPacketSize = 100;
@@ -46,7 +47,7 @@
   RRSendQueueTest()
       : buf_("log: ",
              &callbacks_,
-
+             kMaxQueueSize,
              kMtu,
              kDefaultPriority,
              kBufferedAmountLowThreshold) {}
@@ -59,12 +60,14 @@
 TEST_F(RRSendQueueTest, EmptyBuffer) {
   EXPECT_TRUE(buf_.IsEmpty());
   EXPECT_FALSE(buf_.Produce(kNow, kOneFragmentPacketSize).has_value());
+  EXPECT_FALSE(buf_.IsFull());
 }
 
 TEST_F(RRSendQueueTest, AddAndGetSingleChunk) {
   buf_.Add(kNow, DcSctpMessage(kStreamID, kPPID, {1, 2, 4, 5, 6}));
 
   EXPECT_FALSE(buf_.IsEmpty());
+  EXPECT_FALSE(buf_.IsFull());
   absl::optional<SendQueue::DataToSend> chunk_opt =
       buf_.Produce(kNow, kOneFragmentPacketSize);
   ASSERT_TRUE(chunk_opt.has_value());
@@ -121,30 +124,30 @@
 
 TEST_F(RRSendQueueTest, BufferBecomesFullAndEmptied) {
   std::vector<uint8_t> payload(600);
-  EXPECT_LT(buf_.total_buffered_amount(), 1000u);
+  EXPECT_FALSE(buf_.IsFull());
   buf_.Add(kNow, DcSctpMessage(kStreamID, kPPID, payload));
-  EXPECT_LT(buf_.total_buffered_amount(), 1000u);
+  EXPECT_FALSE(buf_.IsFull());
   buf_.Add(kNow, DcSctpMessage(StreamID(3), PPID(54), payload));
-  EXPECT_GE(buf_.total_buffered_amount(), 1000u);
+  EXPECT_TRUE(buf_.IsFull());
   // However, it's still possible to add messages. It's a soft limit, and it
   // might be necessary to forcefully add messages due to e.g. external
   // fragmentation.
   buf_.Add(kNow, DcSctpMessage(StreamID(5), PPID(55), payload));
-  EXPECT_GE(buf_.total_buffered_amount(), 1000u);
+  EXPECT_TRUE(buf_.IsFull());
 
   absl::optional<SendQueue::DataToSend> chunk_one = buf_.Produce(kNow, 1000);
   ASSERT_TRUE(chunk_one.has_value());
   EXPECT_EQ(chunk_one->data.stream_id, kStreamID);
   EXPECT_EQ(chunk_one->data.ppid, kPPID);
 
-  EXPECT_GE(buf_.total_buffered_amount(), 1000u);
+  EXPECT_TRUE(buf_.IsFull());
 
   absl::optional<SendQueue::DataToSend> chunk_two = buf_.Produce(kNow, 1000);
   ASSERT_TRUE(chunk_two.has_value());
   EXPECT_EQ(chunk_two->data.stream_id, StreamID(3));
   EXPECT_EQ(chunk_two->data.ppid, PPID(54));
 
-  EXPECT_LT(buf_.total_buffered_amount(), 1000u);
+  EXPECT_FALSE(buf_.IsFull());
   EXPECT_FALSE(buf_.IsEmpty());
 
   absl::optional<SendQueue::DataToSend> chunk_three = buf_.Produce(kNow, 1000);
@@ -152,7 +155,7 @@
   EXPECT_EQ(chunk_three->data.stream_id, StreamID(5));
   EXPECT_EQ(chunk_three->data.ppid, PPID(55));
 
-  EXPECT_LT(buf_.total_buffered_amount(), 1000u);
+  EXPECT_FALSE(buf_.IsFull());
   EXPECT_TRUE(buf_.IsEmpty());
 }
 
@@ -810,7 +813,7 @@
   DcSctpSocketHandoverState state;
   buf_.AddHandoverState(state);
 
-  RRSendQueue q2("log: ", &callbacks_, kMtu, kDefaultPriority,
+  RRSendQueue q2("log: ", &callbacks_, kMaxQueueSize, kMtu, kDefaultPriority,
                  kBufferedAmountLowThreshold);
   q2.RestoreFromState(state);
   EXPECT_EQ(q2.GetStreamPriority(StreamID(1)), StreamPriority(42));