Updates to Brotli compression format, decoder and encoder

This commit contains a batch of changes that were made to the Brotli
compression algorithm in the last three weeks. Most important changes:

  * Added UTF8 context model for good text compression.
  * Simplified context modeling by having only 4 context modes.
  * Per-block context mode selection.
  * Faster backward copying and bit reading functions.
  * More efficient histogram coding.
  * Streaming support for the decoder and encoder.

brotli/dec/decode.h

@@ -17,6 +17,7 @@
 #ifndef BROTLI_DEC_DECODE_H_
 #define BROTLI_DEC_DECODE_H_
 
+#include "./streams.h"
 #include "./types.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
@@ -39,6 +40,10 @@ int BrotliDecompressBuffer(size_t encoded_size,
                            size_t* decoded_size,
                            uint8_t* decoded_buffer);
 
+// Same as above, but uses the specified input and output callbacks instead of
+// reading from and writing to pre-allocated memory buffers.
+int BrotliDecompress(BrotliInput input, BrotliOutput output);
+
 #if defined(__cplusplus) || defined(c_plusplus)
 }    // extern "C"
 #endif