Deprecate hpack_table_size flag, remove dead code.

net/spdy/spdy_flags.cc

Index: net/spdy/spdy_flags.cc
diff --git a/net/spdy/spdy_flags.cc b/net/spdy/spdy_flags.cc
index b8975205d687641dedf0f8f984caf7232aba20b0..4ff63c5f9e1c91a968fab6c487fd259fa48cb014 100644
--- a/net/spdy/spdy_flags.cc
+++ b/net/spdy/spdy_flags.cc
@@ -18,10 +18,6 @@ bool FLAGS_chromium_http2_flag_spdy_use_hpack_decoder2 = false;
 // Use //net/http2/hpack/decoder as complete HPACK decoder.
 bool FLAGS_chromium_http2_flag_spdy_use_hpack_decoder3 = true;
 
-// If true, increase HPACK table size up to optimal size kOptTableSize if
-// clients allow it.
-bool FLAGS_chromium_reloadable_flag_increase_hpack_table_size = false;
-
 // Use Http2FrameDecoderAdapter.
 // TODO(jamessynge): Remove flag once no longer set by scripts.
 bool FLAGS_chromium_http2_flag_spdy_use_http2_frame_decoder_adapter = false;