diff --git a/webrtc/base/bitbuffer.h b/webrtc/base/bitbuffer.h
index 09cba3c..b2baaa9 100644
--- a/webrtc/base/bitbuffer.h
+++ b/webrtc/base/bitbuffer.h
@@ -11,9 +11,116 @@
 #ifndef WEBRTC_BASE_BITBUFFER_H_
 #define WEBRTC_BASE_BITBUFFER_H_
 
+#include <stdint.h>  // For integer types.
+#include <stddef.h>  // For size_t.
 
-// This header is deprecated and is just left here temporarily during
-// refactoring. See https://bugs.webrtc.org/7634 for more details.
-#include "webrtc/rtc_base/bitbuffer.h"
+#include "webrtc/base/constructormagic.h"
+
+namespace rtc {
+
+// A class, similar to ByteBuffer, that can parse bit-sized data out of a set of
+// bytes. Has a similar API to ByteBuffer, plus methods for reading bit-sized
+// and exponential golomb encoded data. For a writable version, use
+// BitBufferWriter. Unlike ByteBuffer, this class doesn't make a copy of the
+// source bytes, so it can be used on read-only data.
+// Sizes/counts specify bits/bytes, for clarity.
+// Byte order is assumed big-endian/network.
+class BitBuffer {
+ public:
+  BitBuffer(const uint8_t* bytes, size_t byte_count);
+
+  // Gets the current offset, in bytes/bits, from the start of the buffer. The
+  // bit offset is the offset into the current byte, in the range [0,7].
+  void GetCurrentOffset(size_t* out_byte_offset, size_t* out_bit_offset);
+
+  // The remaining bits in the byte buffer.
+  uint64_t RemainingBitCount() const;
+
+  // Reads byte-sized values from the buffer. Returns false if there isn't
+  // enough data left for the specified type.
+  bool ReadUInt8(uint8_t* val);
+  bool ReadUInt16(uint16_t* val);
+  bool ReadUInt32(uint32_t* val);
+
+  // Reads bit-sized values from the buffer. Returns false if there isn't enough
+  // data left for the specified bit count..
+  bool ReadBits(uint32_t* val, size_t bit_count);
+
+  // Peeks bit-sized values from the buffer. Returns false if there isn't enough
+  // data left for the specified number of bits. Doesn't move the current
+  // offset.
+  bool PeekBits(uint32_t* val, size_t bit_count);
+
+  // Reads the exponential golomb encoded value at the current offset.
+  // Exponential golomb values are encoded as:
+  // 1) x = source val + 1
+  // 2) In binary, write [countbits(x) - 1] 0s, then x
+  // To decode, we count the number of leading 0 bits, read that many + 1 bits,
+  // and increment the result by 1.
+  // Returns false if there isn't enough data left for the specified type, or if
+  // the value wouldn't fit in a uint32_t.
+  bool ReadExponentialGolomb(uint32_t* val);
+  // Reads signed exponential golomb values at the current offset. Signed
+  // exponential golomb values are just the unsigned values mapped to the
+  // sequence 0, 1, -1, 2, -2, etc. in order.
+  bool ReadSignedExponentialGolomb(int32_t* val);
+
+  // Moves current position |byte_count| bytes forward. Returns false if
+  // there aren't enough bytes left in the buffer.
+  bool ConsumeBytes(size_t byte_count);
+  // Moves current position |bit_count| bits forward. Returns false if
+  // there aren't enough bits left in the buffer.
+  bool ConsumeBits(size_t bit_count);
+
+  // Sets the current offset to the provied byte/bit offsets. The bit
+  // offset is from the given byte, in the range [0,7].
+  bool Seek(size_t byte_offset, size_t bit_offset);
+
+ protected:
+  const uint8_t* const bytes_;
+  // The total size of |bytes_|.
+  size_t byte_count_;
+  // The current offset, in bytes, from the start of |bytes_|.
+  size_t byte_offset_;
+  // The current offset, in bits, into the current byte.
+  size_t bit_offset_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(BitBuffer);
+};
+
+// A BitBuffer API for write operations. Supports symmetric write APIs to the
+// reading APIs of BitBuffer. Note that the read/write offset is shared with the
+// BitBuffer API, so both reading and writing will consume bytes/bits.
+class BitBufferWriter : public BitBuffer {
+ public:
+  // Constructs a bit buffer for the writable buffer of |bytes|.
+  BitBufferWriter(uint8_t* bytes, size_t byte_count);
+
+  // Writes byte-sized values from the buffer. Returns false if there isn't
+  // enough data left for the specified type.
+  bool WriteUInt8(uint8_t val);
+  bool WriteUInt16(uint16_t val);
+  bool WriteUInt32(uint32_t val);
+
+  // Writes bit-sized values to the buffer. Returns false if there isn't enough
+  // room left for the specified number of bits.
+  bool WriteBits(uint64_t val, size_t bit_count);
+
+  // Writes the exponential golomb encoded version of the supplied value.
+  // Returns false if there isn't enough room left for the value.
+  bool WriteExponentialGolomb(uint32_t val);
+  // Writes the signed exponential golomb version of the supplied value.
+  // Signed exponential golomb values are just the unsigned values mapped to the
+  // sequence 0, 1, -1, 2, -2, etc. in order.
+  bool WriteSignedExponentialGolomb(int32_t val);
+
+ private:
+  // The buffer, as a writable array.
+  uint8_t* const writable_bytes_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(BitBufferWriter);
+};
+
+}  // namespace rtc
 
 #endif  // WEBRTC_BASE_BITBUFFER_H_