Reduce visibility to internals of the flatbuffer repository.

Rather than defaulting to public, default to private and explicitly mark the
targets that should be externally visible. This causes the visibility to line up
with what is available in the BUILD.system file.

PiperOrigin-RevId: 292064746
Change-Id: I4964983457b3e5f31200531fe35f2aa316c73833

third_party/flatbuffers/BUILD.bazel

@@ -1,7 +1,3 @@
-package(
-    default_visibility = ["//visibility:public"],
-)
-
 licenses(["notice"])  # Apache 2.0
 
 exports_files(["LICENSE.txt"])
@@ -11,7 +7,6 @@ licenses(["notice"])
 config_setting(
     name = "freebsd",
     values = {"cpu": "freebsd"},
-    visibility = ["//visibility:public"],
 )
 
 config_setting(
@@ -27,6 +22,7 @@ cc_library(
     hdrs = ["//:public_headers"],
     linkstatic = 1,
     strip_include_prefix = "/include",
+    visibility = ["//visibility:public"],
     deps = ["//src:flatbuffers"],
 )
 
@@ -47,12 +43,14 @@ filegroup(
         "include/flatbuffers/stl_emulation.h",
         "include/flatbuffers/util.h",
     ],
+    visibility = ["//:__subpackages__"],
 )
 
 # Public flatc compiler library.
 cc_library(
     name = "flatc_library",
     linkstatic = 1,
+    visibility = ["//visibility:public"],
     deps = [
         "@flatbuffers//src:flatc_library",
     ],
@@ -71,6 +69,7 @@ cc_binary(
             "-ldl",
         ],
     }),
+    visibility = ["//visibility:public"],
     deps = [
         "@flatbuffers//src:flatc",
     ],
@@ -96,6 +95,7 @@ cc_library(
     ],
     linkstatic = 1,
     strip_include_prefix = "/include",
+    visibility = ["//visibility:public"],
 )
 
 filegroup(
@@ -114,4 +114,5 @@ filegroup(
 py_library(
     name = "runtime_py",
     srcs = [":runtime_py_srcs"],
+    visibility = ["//visibility:public"],
 )