experiment with -Wimplicit-fallthrough

net/base/gzip_filter.cc

 // Copyright (c) 2011 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.
 
 #include "net/base/gzip_filter.h"
 
 #include "base/logging.h"
 #include "net/base/gzip_header.h"
 #include "third_party/zlib/zlib.h"
 
@@ skipping 28 matching lines @@
   switch (filter_type) {
     case Filter::FILTER_TYPE_DEFLATE: {
       if (inflateInit(zlib_stream_.get()) != Z_OK)
         return false;
       decoding_mode_ = DECODE_MODE_DEFLATE;
       break;
     }
     case Filter::FILTER_TYPE_GZIP_HELPING_SDCH:
       possible_sdch_pass_through_ =  true;  // Needed to optionally help sdch.
       // Fall through to GZIP case.
+      FALLTHROUGH_INTENDED;
     case Filter::FILTER_TYPE_GZIP: {
       gzip_header_.reset(new GZipHeader());
       if (!gzip_header_.get())
         return false;
       if (inflateInit2(zlib_stream_.get(), -MAX_WBITS) != Z_OK)
         return false;
       decoding_mode_ = DECODE_MODE_GZIP;
       break;
     }
     default: {
@@ skipping 230 matching lines @@
     stream_data_len_ -= footer_byte_avail;
     next_stream_data_ += footer_byte_avail;
     gzip_footer_bytes_ += footer_byte_avail;
 
     if (stream_data_len_ == 0)
       next_stream_data_ = NULL;
   }
 }
 
 }  // namespace net