Remove locks from BufferQueue (not needed).

Also remove test code that can cause leaks into production.
Add sequence checkers.

Bug: webrtc:11988
Change-Id: I67b4cec6ee77d73ccffbbc88c9081ebb3c3cc423
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/185503
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32228}
diff --git a/rtc_base/buffer_queue.cc b/rtc_base/buffer_queue.cc
index adad9dd..7879e93 100644
--- a/rtc_base/buffer_queue.cc
+++ b/rtc_base/buffer_queue.cc
@@ -21,23 +21,20 @@
     : capacity_(capacity), default_size_(default_size) {}
 
 BufferQueue::~BufferQueue() {
-  webrtc::MutexLock lock(&mutex_);
-
-  for (Buffer* buffer : queue_) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  for (Buffer* buffer : queue_)
     delete buffer;
-  }
-  for (Buffer* buffer : free_list_) {
+  for (Buffer* buffer : free_list_)
     delete buffer;
-  }
 }
 
 size_t BufferQueue::size() const {
-  webrtc::MutexLock lock(&mutex_);
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
   return queue_.size();
 }
 
 void BufferQueue::Clear() {
-  webrtc::MutexLock lock(&mutex_);
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
   while (!queue_.empty()) {
     free_list_.push_back(queue_.front());
     queue_.pop_front();
@@ -45,36 +42,30 @@
 }
 
 bool BufferQueue::ReadFront(void* buffer, size_t bytes, size_t* bytes_read) {
-  webrtc::MutexLock lock(&mutex_);
-  if (queue_.empty()) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  if (queue_.empty())
     return false;
-  }
 
-  bool was_writable = queue_.size() < capacity_;
   Buffer* packet = queue_.front();
   queue_.pop_front();
 
   bytes = std::min(bytes, packet->size());
   memcpy(buffer, packet->data(), bytes);
-  if (bytes_read) {
+
+  if (bytes_read)
     *bytes_read = bytes;
-  }
+
   free_list_.push_back(packet);
-  if (!was_writable) {
-    NotifyWritableForTest();
-  }
   return true;
 }
 
 bool BufferQueue::WriteBack(const void* buffer,
                             size_t bytes,
                             size_t* bytes_written) {
-  webrtc::MutexLock lock(&mutex_);
-  if (queue_.size() == capacity_) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  if (queue_.size() == capacity_)
     return false;
-  }
 
-  bool was_readable = !queue_.empty();
   Buffer* packet;
   if (!free_list_.empty()) {
     packet = free_list_.back();
@@ -84,13 +75,10 @@
   }
 
   packet->SetData(static_cast<const uint8_t*>(buffer), bytes);
-  if (bytes_written) {
+  if (bytes_written)
     *bytes_written = bytes;
-  }
+
   queue_.push_back(packet);
-  if (!was_readable) {
-    NotifyReadableForTest();
-  }
   return true;
 }