Factor out grpc_add_default_authority_if_not_present
diff --git a/BUILD b/BUILD
index a511896..b56e6e4 100644
--- a/BUILD
+++ b/BUILD
@@ -682,11 +682,11 @@
         "src/core/lib/channel/channel_stack_builder.cc",
         "src/core/lib/channel/channel_trace.cc",
         "src/core/lib/channel/channel_trace_registry.cc",
-        "src/core/lib/channel/status_util.cc",
         "src/core/lib/channel/connected_channel.cc",
         "src/core/lib/channel/handshaker.cc",
         "src/core/lib/channel/handshaker_factory.cc",
         "src/core/lib/channel/handshaker_registry.cc",
+        "src/core/lib/channel/status_util.cc",
         "src/core/lib/compression/compression.cc",
         "src/core/lib/compression/compression_internal.cc",
         "src/core/lib/compression/message_compress.cc",
@@ -829,12 +829,12 @@
         "src/core/lib/channel/channel_stack_builder.h",
         "src/core/lib/channel/channel_trace.h",
         "src/core/lib/channel/channel_trace_registry.h",
-        "src/core/lib/channel/status_util.h",
         "src/core/lib/channel/connected_channel.h",
         "src/core/lib/channel/context.h",
         "src/core/lib/channel/handshaker.h",
         "src/core/lib/channel/handshaker_factory.h",
         "src/core/lib/channel/handshaker_registry.h",
+        "src/core/lib/channel/status_util.h",
         "src/core/lib/compression/algorithm_metadata.h",
         "src/core/lib/compression/compression_internal.h",
         "src/core/lib/compression/message_compress.h",
@@ -1009,6 +1009,7 @@
 grpc_cc_library(
     name = "grpc_client_channel",
     srcs = [
+        "src/core/ext/filters/client_channel/authority.cc",
         "src/core/ext/filters/client_channel/backup_poller.cc",
         "src/core/ext/filters/client_channel/channel_connectivity.cc",
         "src/core/ext/filters/client_channel/client_channel.cc",
@@ -1032,6 +1033,7 @@
         "src/core/ext/filters/client_channel/uri_parser.cc",
     ],
     hdrs = [
+        "src/core/ext/filters/client_channel/authority.h",
         "src/core/ext/filters/client_channel/backup_poller.h",
         "src/core/ext/filters/client_channel/client_channel.h",
         "src/core/ext/filters/client_channel/client_channel_factory.h",