Revert "Revert "Metadata handling rewrite""

This reverts commit 5e01e2ac977655aa074faf7fde0a74298f5e4c55.
diff --git a/grpc.gemspec b/grpc.gemspec
index 3568515..a85be4e 100755
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -191,6 +191,7 @@
   s.files += %w( src/core/lib/iomgr/endpoint.h )
   s.files += %w( src/core/lib/iomgr/endpoint_pair.h )
   s.files += %w( src/core/lib/iomgr/error.h )
+  s.files += %w( src/core/lib/iomgr/error_internal.h )
   s.files += %w( src/core/lib/iomgr/ev_epoll_linux.h )
   s.files += %w( src/core/lib/iomgr/ev_poll_posix.h )
   s.files += %w( src/core/lib/iomgr/ev_posix.h )
@@ -243,6 +244,7 @@
   s.files += %w( src/core/lib/json/json_reader.h )
   s.files += %w( src/core/lib/json/json_writer.h )
   s.files += %w( src/core/lib/slice/percent_encoding.h )
+  s.files += %w( src/core/lib/slice/slice_hash_table.h )
   s.files += %w( src/core/lib/slice/slice_internal.h )
   s.files += %w( src/core/lib/slice/slice_string_helpers.h )
   s.files += %w( src/core/lib/surface/api_trace.h )
@@ -256,14 +258,17 @@
   s.files += %w( src/core/lib/surface/init.h )
   s.files += %w( src/core/lib/surface/lame_client.h )
   s.files += %w( src/core/lib/surface/server.h )
+  s.files += %w( src/core/lib/surface/validate_metadata.h )
   s.files += %w( src/core/lib/transport/byte_stream.h )
   s.files += %w( src/core/lib/transport/connectivity_state.h )
-  s.files += %w( src/core/lib/transport/mdstr_hash_table.h )
+  s.files += %w( src/core/lib/transport/error_utils.h )
+  s.files += %w( src/core/lib/transport/http2_errors.h )
   s.files += %w( src/core/lib/transport/metadata.h )
   s.files += %w( src/core/lib/transport/metadata_batch.h )
   s.files += %w( src/core/lib/transport/pid_controller.h )
   s.files += %w( src/core/lib/transport/service_config.h )
   s.files += %w( src/core/lib/transport/static_metadata.h )
+  s.files += %w( src/core/lib/transport/status_conversion.h )
   s.files += %w( src/core/lib/transport/timeout_encoding.h )
   s.files += %w( src/core/lib/transport/transport.h )
   s.files += %w( src/core/lib/transport/transport_impl.h )
@@ -280,11 +285,9 @@
   s.files += %w( src/core/ext/transport/chttp2/transport/hpack_encoder.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/hpack_parser.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/hpack_table.h )
-  s.files += %w( src/core/ext/transport/chttp2/transport/http2_errors.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/huffsyms.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/incoming_metadata.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/internal.h )
-  s.files += %w( src/core/ext/transport/chttp2/transport/status_conversion.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/stream_map.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/varint.h )
   s.files += %w( src/core/ext/transport/chttp2/alpn/alpn.h )
@@ -434,6 +437,8 @@
   s.files += %w( src/core/lib/slice/percent_encoding.c )
   s.files += %w( src/core/lib/slice/slice.c )
   s.files += %w( src/core/lib/slice/slice_buffer.c )
+  s.files += %w( src/core/lib/slice/slice_hash_table.c )
+  s.files += %w( src/core/lib/slice/slice_intern.c )
   s.files += %w( src/core/lib/slice/slice_string_helpers.c )
   s.files += %w( src/core/lib/surface/alarm.c )
   s.files += %w( src/core/lib/surface/api_trace.c )
@@ -455,12 +460,13 @@
   s.files += %w( src/core/lib/surface/version.c )
   s.files += %w( src/core/lib/transport/byte_stream.c )
   s.files += %w( src/core/lib/transport/connectivity_state.c )
-  s.files += %w( src/core/lib/transport/mdstr_hash_table.c )
+  s.files += %w( src/core/lib/transport/error_utils.c )
   s.files += %w( src/core/lib/transport/metadata.c )
   s.files += %w( src/core/lib/transport/metadata_batch.c )
   s.files += %w( src/core/lib/transport/pid_controller.c )
   s.files += %w( src/core/lib/transport/service_config.c )
   s.files += %w( src/core/lib/transport/static_metadata.c )
+  s.files += %w( src/core/lib/transport/status_conversion.c )
   s.files += %w( src/core/lib/transport/timeout_encoding.c )
   s.files += %w( src/core/lib/transport/transport.c )
   s.files += %w( src/core/lib/transport/transport_op_string.c )
@@ -481,7 +487,6 @@
   s.files += %w( src/core/ext/transport/chttp2/transport/huffsyms.c )
   s.files += %w( src/core/ext/transport/chttp2/transport/incoming_metadata.c )
   s.files += %w( src/core/ext/transport/chttp2/transport/parsing.c )
-  s.files += %w( src/core/ext/transport/chttp2/transport/status_conversion.c )
   s.files += %w( src/core/ext/transport/chttp2/transport/stream_lists.c )
   s.files += %w( src/core/ext/transport/chttp2/transport/stream_map.c )
   s.files += %w( src/core/ext/transport/chttp2/transport/varint.c )