Clean up deprecated sources assignment filter in //sandbox

Remove deprecated_default_sources_assignment_filter and replace
it with explicit is_win, is_mac, etc. sections.

Bug: 1018739
Change-Id: I9a5412ea3b92fd3322bb26b062b829a457dba7c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2443249Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813139}

sandbox/linux/BUILD.gn

@@ -11,13 +11,6 @@ if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
-# This file depends on the legacy global sources assignment filter. It should
-# be converted to check target platform before assigning source files to the
-# sources variable. Remove this import and set_sources_assignment_filter call
-# when the file has been converted. See https://crbug.com/1018739 for details.
-import("//build/config/deprecated_default_sources_assignment_filter.gni")
-set_sources_assignment_filter(deprecated_default_sources_assignment_filter)
-
 declare_args() {
   compile_suid_client = is_linux || is_chromeos
 
@@ -232,8 +225,6 @@ component("seccomp_bpf") {
     "bpf_dsl/trap_registry.h",
     "seccomp-bpf-helpers/baseline_policy.cc",
     "seccomp-bpf-helpers/baseline_policy.h",
-    "seccomp-bpf-helpers/baseline_policy_android.cc",
-    "seccomp-bpf-helpers/baseline_policy_android.h",
     "seccomp-bpf-helpers/sigsys_handlers.cc",
     "seccomp-bpf-helpers/sigsys_handlers.h",
     "seccomp-bpf-helpers/syscall_parameters_restrictions.cc",
@@ -262,6 +253,13 @@ component("seccomp_bpf") {
     "//sandbox:sandbox_buildflags",
   ]
 
+  if (is_android) {
+    sources += [
+      "seccomp-bpf-helpers/baseline_policy_android.cc",
+      "seccomp-bpf-helpers/baseline_policy_android.h",
+    ]
+  }
+
   if (is_nacl_nonsfi) {
     cflags = [ "-fgnu-inline-asm" ]
     sources -= [