Reland "Move webrtc/{base => rtc_base}" (https://codereview.webrtc.org/2877023002)

Reland the base->rtc_base without adding stub headers (will be
done in follow-up CL). This preserves git blame history of all files.

BUG=webrtc:7634
NOTRY=True
TBR=kwiberg@webrtc.org

Change-Id: Iea3bb6f3f67b8374c96337b63e8f5aa3e6181012
Reviewed-on: https://chromium-review.googlesource.com/554611
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#18821}

webrtc/rtc_base/bufferqueue.h

@@ -0,0 +1,61 @@
+/*
+ *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_RTC_BASE_BUFFERQUEUE_H_
+#define WEBRTC_RTC_BASE_BUFFERQUEUE_H_
+
+#include <deque>
+#include <vector>
+
+#include "webrtc/base/buffer.h"
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/base/criticalsection.h"
+
+namespace rtc {
+
+class BufferQueue {
+ public:
+  // Creates a buffer queue with a given capacity and default buffer size.
+  BufferQueue(size_t capacity, size_t default_size);
+  virtual ~BufferQueue();
+
+  // Return number of queued buffers.
+  size_t size() const;
+
+  // Clear the BufferQueue by moving all Buffers from |queue_| to |free_list_|.
+  void Clear();
+
+  // ReadFront will only read one buffer at a time and will truncate buffers
+  // that don't fit in the passed memory.
+  // Returns true unless no data could be returned.
+  bool ReadFront(void* data, size_t bytes, size_t* bytes_read);
+
+  // WriteBack always writes either the complete memory or nothing.
+  // Returns true unless no data could be written.
+  bool WriteBack(const void* data, size_t bytes, size_t* bytes_written);
+
+ protected:
+  // These methods are called when the state of the queue changes.
+  virtual void NotifyReadableForTest() {}
+  virtual void NotifyWritableForTest() {}
+
+ private:
+  size_t capacity_;
+  size_t default_size_;
+  CriticalSection crit_;
+  std::deque<Buffer*> queue_ GUARDED_BY(crit_);
+  std::vector<Buffer*> free_list_ GUARDED_BY(crit_);
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(BufferQueue);
+};
+
+}  // namespace rtc
+
+#endif  // WEBRTC_RTC_BASE_BUFFERQUEUE_H_