[Sync] Convert sync to a static library.

components/sync/protocol/BUILD.gn

Index: components/sync/protocol/BUILD.gn
diff --git a/components/sync/protocol/BUILD.gn b/components/sync/protocol/BUILD.gn
index 209f26ccf28923f4a14abb8bdf03b623d5763bb6..50c3e7fa9a627543569d4bc221c81323475aa576 100644
--- a/components/sync/protocol/BUILD.gn
+++ b/components/sync/protocol/BUILD.gn
@@ -5,24 +5,7 @@
 import("//third_party/protobuf/proto_library.gni")
 import("protocol_sources.gni")
 
-# This must be a component for the dependency structure we have now, but the
-# proto_library generates a source set. Link those into a component.
-component("protocol") {
-  public_deps = [
-    ":protocol_internal",
-  ]
-}
-
-proto_library("protocol_internal") {
-  visibility = [ ":protocol" ]
-
+proto_library("protocol") {
   sources = sync_protocol_sources
-
-  cc_generator_options = "dllexport_decl=SYNC_PROTO_EXPORT:"
-  cc_include = "components/sync/protocol/sync_proto_export.h"
-  component_build_force_source_set = true
-
-  defines = [ "SYNC_PROTO_IMPLEMENTATION" ]
-
   extra_configs = [ "//build/config/compiler:wexit_time_destructors" ]
 }