Update BUILD.gn after recent gRPC roll.

BUG=
R=gcasto@chromium.org

Review URL: https://codereview.chromium.org/2160213003 .
diff --git a/BUILD.gn b/BUILD.gn
index f375c33..4248a64 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -24,7 +24,6 @@
     "src/core/lib/support/backoff.h",
     "src/core/lib/support/block_annotate.h",
     "src/core/lib/support/env.h",
-    "src/core/lib/support/load_file.h",
     "src/core/lib/support/murmur_hash.h",
     "src/core/lib/support/stack_lockfree.h",
     "src/core/lib/support/string.h",
@@ -47,7 +46,6 @@
     "src/core/lib/support/env_windows.c",
     "src/core/lib/support/histogram.c",
     "src/core/lib/support/host_port.c",
-    "src/core/lib/support/load_file.c",
     "src/core/lib/support/log.c",
     "src/core/lib/support/log_android.c",
     "src/core/lib/support/log_linux.c",
@@ -147,6 +145,8 @@
     "src/core/lib/iomgr/closure.h",
     "src/core/lib/iomgr/endpoint.h",
     "src/core/lib/iomgr/endpoint_pair.h",
+    "src/core/lib/iomgr/error.h",
+    "src/core/lib/iomgr/ev_epoll_linux.h",
     "src/core/lib/iomgr/ev_poll_and_epoll_posix.h",
     "src/core/lib/iomgr/ev_poll_posix.h",
     "src/core/lib/iomgr/ev_posix.h",
@@ -156,6 +156,8 @@
     "src/core/lib/iomgr/iomgr.h",
     "src/core/lib/iomgr/iomgr_internal.h",
     "src/core/lib/iomgr/iomgr_posix.h",
+    "src/core/lib/iomgr/load_file.h",
+    "src/core/lib/iomgr/network_status_tracker.h",
     "src/core/lib/iomgr/polling_entity.h",
     "src/core/lib/iomgr/pollset.h",
     "src/core/lib/iomgr/pollset_set.h",
@@ -197,7 +199,6 @@
     "src/core/lib/surface/init.h",
     "src/core/lib/surface/lame_client.h",
     "src/core/lib/surface/server.h",
-    "src/core/lib/surface/surface_trace.h",
     "src/core/lib/transport/byte_stream.h",
     "src/core/lib/transport/connectivity_state.h",
     "src/core/lib/transport/metadata.h",
@@ -205,6 +206,7 @@
     "src/core/lib/transport/static_metadata.h",
     "src/core/lib/transport/transport.h",
     "src/core/lib/transport/transport_impl.h",
+    "src/core/ext/transport/chttp2/transport/bin_decoder.h",
     "src/core/ext/transport/chttp2/transport/bin_encoder.h",
     "src/core/ext/transport/chttp2/transport/chttp2_transport.h",
     "src/core/ext/transport/chttp2/transport/frame.h",
@@ -269,6 +271,8 @@
     "src/core/lib/iomgr/endpoint.c",
     "src/core/lib/iomgr/endpoint_pair_posix.c",
     "src/core/lib/iomgr/endpoint_pair_windows.c",
+    "src/core/lib/iomgr/error.c",
+    "src/core/lib/iomgr/ev_epoll_linux.c",
     "src/core/lib/iomgr/ev_poll_and_epoll_posix.c",
     "src/core/lib/iomgr/ev_poll_posix.c",
     "src/core/lib/iomgr/ev_posix.c",
@@ -278,6 +282,8 @@
     "src/core/lib/iomgr/iomgr.c",
     "src/core/lib/iomgr/iomgr_posix.c",
     "src/core/lib/iomgr/iomgr_windows.c",
+    "src/core/lib/iomgr/load_file.c",
+    "src/core/lib/iomgr/network_status_tracker.c",
     "src/core/lib/iomgr/polling_entity.c",
     "src/core/lib/iomgr/pollset_set_windows.c",
     "src/core/lib/iomgr/pollset_windows.c",
@@ -337,6 +343,7 @@
     "src/core/lib/transport/transport_op_string.c",
     "src/core/ext/transport/chttp2/server/insecure/server_chttp2.c",
     "src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c",
+    "src/core/ext/transport/chttp2/transport/bin_decoder.c",
     "src/core/ext/transport/chttp2/transport/bin_encoder.c",
     "src/core/ext/transport/chttp2/transport/chttp2_plugin.c",
     "src/core/ext/transport/chttp2/transport/chttp2_transport.c",