Add brotli content-encoding filter.

net/filter/filter.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Filter performs filtering on data streams. Sample usage:
 //
 //   IStream* pre_filter_source;
 //   ...
 //   Filter* filter = Filter::Factory(filter_type, size);
 //   int pre_filter_data_len = filter->stream_buffer_size();
@@ skipping 110 matching lines @@
 
   // The URLRequestContext associated with the request.
   virtual const URLRequestContext* GetURLRequestContext() const = 0;
 
   // The following method forces the context to emit a specific set of
   // statistics as selected by the argument.
   virtual void RecordPacketStats(StatisticSelector statistic) const = 0;
 
   // The BoundNetLog of the associated request.
   virtual const BoundNetLog& GetNetLog() const = 0;
+
+  virtual bool IsBrotliEnabled() const = 0;
 };
 
 //------------------------------------------------------------------------------
 class NET_EXPORT_PRIVATE Filter {
  public:
   // Return values of function ReadFilteredData.
   enum FilterStatus {
     // Read filtered data successfully
     FILTER_OK,
     // Read filtered data successfully, and the data in the buffer has been
     // consumed by the filter, but more data is needed in order to continue
     // filtering. At this point, the caller is free to reuse the filter
     // buffer to provide more data.
     FILTER_NEED_MORE_DATA,
     // Read filtered data successfully, and filter reaches the end of the data
     // stream.
     FILTER_DONE,
     // There is an error during filtering.
     FILTER_ERROR
   };
 
   // Specifies type of filters that can be created.
   enum FilterType {
+    FILTER_TYPE_BROTLI,
     FILTER_TYPE_DEFLATE,
     FILTER_TYPE_GZIP,
     FILTER_TYPE_GZIP_HELPING_SDCH,  // Gzip possible, but pass through allowed.
     FILTER_TYPE_SDCH,
     FILTER_TYPE_SDCH_POSSIBLE,  // Sdch possible, but pass through allowed.
     FILTER_TYPE_UNSUPPORTED,
   };
 
   virtual ~Filter();
 
@@ skipping 60 matching lines @@
   // encodings. These fixups require context, which includes whether this
   // response was made to an SDCH request (i.e., an available dictionary was
   // advertised in the GET), as well as the mime type of the content.
   static void FixupEncodingTypes(const FilterContext& filter_context,
                                  std::vector<FilterType>* encoding_types);
 
   // Returns a string describing the FilterTypes implemented by this filter.
   std::string OrderedFilterList() const;
 
  protected:
+  friend class BrotliUnitTest;
   friend class GZipUnitTest;
   friend class SdchFilterChainingTest;
   FRIEND_TEST_ALL_PREFIXES(FilterTest, ThreeFilterChain);
 
   explicit Filter(FilterType type_id);
 
   // Filters the data stored in stream_buffer_ and writes the output into the
   // dest_buffer passed in.
   //
   // Upon entry, *dest_len is the total size (in number of chars) of the
@@ skipping 32 matching lines @@
   // called multiple times during the filter creation process. In most simple
   // cases, this is only called once. Returns NULL and cleans up (deleting
   // filter_list) if a new filter can't be constructed.
   static Filter* PrependNewFilter(FilterType type_id,
                                   const FilterContext& filter_context,
                                   int buffer_size,
                                   Filter* filter_list);
 
   // Helper methods for PrependNewFilter. If initialization is successful,
   // they return a fully initialized Filter. Otherwise, return NULL.
+  static Filter* InitBrotliFilter(FilterType type_id, int buffer_size);
   static Filter* InitGZipFilter(FilterType type_id, int buffer_size);
   static Filter* InitSdchFilter(FilterType type_id,
                                 const FilterContext& filter_context,
                                 int buffer_size);
 
   // Helper function to empty our output into the next filter's input.
   void PushDataIntoNextFilter();
 
   // Constructs a filter with an internal buffer of the given size.
   // Only meant to be called by unit tests that need to control the buffer size.
@@ skipping 10 matching lines @@
 
   // The filter type this filter was constructed from.
   FilterType type_id_;
 
   DISALLOW_COPY_AND_ASSIGN(Filter);
 };
 
 }  // namespace net
 
 #endif  // NET_FILTER_FILTER_H__