diff --git a/chromeos/lacros/BUILD.gn b/chromeos/lacros/BUILD.gn
index e6d46425099d6..4e3f0c7e5ab48 100644
--- a/chromeos/lacros/BUILD.gn
+++ b/chromeos/lacros/BUILD.gn
@@ -10,12 +10,6 @@ import("//build/lacros/lacros_resource_sizes.gni")
 assert(chromeos_is_browser_only)
 assert(!use_gtk)
 
-# Reset sources_assignment_filter for the BUILD.gn file to prevent
-# regression during the migration of Chromium away from the feature.
-# See docs/no_sources_assignment_filter.md for more information.
-# TODO(crbug.com/1018739): remove this when migration is done.
-set_sources_assignment_filter([])
-
 component("lacros") {
   defines = [ "IS_CHROMEOS_LACROS_IMPL" ]
   deps = [
diff --git a/crypto/BUILD.gn b/crypto/BUILD.gn
index 2464e69b4d084..c0efa3a8e260d 100644
--- a/crypto/BUILD.gn
+++ b/crypto/BUILD.gn
@@ -5,12 +5,6 @@
 import("//build/config/crypto.gni")
 import("//testing/test.gni")
 
-# Reset sources_assignment_filter for the BUILD.gn file to prevent
-# regression during the migration of Chromium away from the feature.
-# See docs/no_sources_assignment_filter.md for more information.
-# TODO(crbug.com/1018739): remove this when migration is done.
-set_sources_assignment_filter([])
-
 component("crypto") {
   output_name = "crcrypto"  # Avoid colliding with OpenSSL's libcrypto.
   sources = [
diff --git a/ipc/BUILD.gn b/ipc/BUILD.gn
index 48bdc5061eb5e..4bcfb300e2892 100644
--- a/ipc/BUILD.gn
+++ b/ipc/BUILD.gn
@@ -10,12 +10,6 @@ import("//testing/test.gni")
 import("//third_party/protobuf/proto_library.gni")
 import("//tools/ipc_fuzzer/ipc_fuzzer.gni")
 
-# Reset sources_assignment_filter for the BUILD.gn file to prevent
-# regression during the migration of Chromium away from the feature.
-# See docs/no_sources_assignment_filter.md for more information.
-# TODO(crbug.com/1018739): remove this when migration is done.
-set_sources_assignment_filter([])
-
 buildflag_header("ipc_buildflags") {
   header = "ipc_buildflags.h"
 
diff --git a/net/BUILD.gn b/net/BUILD.gn
index c399590e2b02d..7915b57b3571e 100644
--- a/net/BUILD.gn
+++ b/net/BUILD.gn
@@ -103,12 +103,6 @@ if (is_linux || is_chromeos) {
   net_configs += [ "//build/config/linux:libresolv" ]
 }
 
-# Reset sources_assignment_filter for the BUILD.gn file to prevent
-# regression during the migration of Chromium away from the feature.
-# See docs/no_sources_assignment_filter.md for more information.
-# TODO(crbug.com/1018739): Remove this when migration is done.
-set_sources_assignment_filter([])
-
 source_set("constants") {
   sources = [ "base/trace_constants.h" ]
   deps = [ "//base" ]
diff --git a/net/dns/BUILD.gn b/net/dns/BUILD.gn
index cf884bbc69e8a..441b68ea86bb1 100644
--- a/net/dns/BUILD.gn
+++ b/net/dns/BUILD.gn
@@ -5,12 +5,6 @@
 import("//net/features.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 
-# Reset sources_assignment_filter for the BUILD.gn file to prevent
-# regression during the migration of Chromium away from the feature.
-# See docs/no_sources_assignment_filter.md for more information.
-# TODO(crbug.com/1018739): remove this when migration is done.
-set_sources_assignment_filter([])
-
 enable_built_in_dns = !is_ios
 
 source_set("dns") {
diff --git a/printing/BUILD.gn b/printing/BUILD.gn
index e67ae47161c5a..005fd1eb0960f 100644
--- a/printing/BUILD.gn
+++ b/printing/BUILD.gn
@@ -18,12 +18,6 @@ if (use_cups && is_chromeos) {
   import("//printing/backend/tools/code_generator.gni")
 }
 
-# Reset sources_assignment_filter for the BUILD.gn file to prevent
-# regression during the migration of Chromium away from the feature.
-# See docs/no_sources_assignment_filter.md for more information.
-# TODO(crbug.com/1018739): remove this when migration is done.
-set_sources_assignment_filter([])
-
 if ((enable_basic_printing && is_win) || enable_print_preview) {
   # Windows basic printing or print preview requires pdf enabled.
   assert(enable_pdf,
diff --git a/remoting/base/BUILD.gn b/remoting/base/BUILD.gn
index 35628d0e5a5b4..12e15e3a55a51 100644
--- a/remoting/base/BUILD.gn
+++ b/remoting/base/BUILD.gn
@@ -4,12 +4,6 @@
 
 import("//third_party/protobuf/proto_library.gni")
 
-# Reset sources_assignment_filter for the BUILD.gn file to prevent
-# regression during the migration of Chromium away from the feature.
-# See docs/no_sources_assignment_filter.md for more information.
-# TODO(crbug.com/1018739): remove this when migration is done.
-set_sources_assignment_filter([])
-
 proto_library("protobuf_http_client_messages_proto") {
   sources = [ "protobuf_http_client_messages.proto" ]
 }
diff --git a/remoting/client/audio/BUILD.gn b/remoting/client/audio/BUILD.gn
index a84301a467788..2ab030bfc12a7 100644
--- a/remoting/client/audio/BUILD.gn
+++ b/remoting/client/audio/BUILD.gn
@@ -2,12 +2,6 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-# Reset sources_assignment_filter for the BUILD.gn file to prevent
-# regression during the migration of Chromium away from the feature.
-# See docs/no_sources_assignment_filter.md for more information.
-# TODO(crbug.com/1018739): remove this when migration is done.
-set_sources_assignment_filter([])
-
 source_set("audio") {
   sources = [
     "async_audio_data_supplier.cc",
diff --git a/remoting/client/input/BUILD.gn b/remoting/client/input/BUILD.gn
index 97cb32df90af0..9de3c0fc600c8 100644
--- a/remoting/client/input/BUILD.gn
+++ b/remoting/client/input/BUILD.gn
@@ -2,12 +2,6 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-# Reset sources_assignment_filter for the BUILD.gn file to prevent
-# regression during the migration of Chromium away from the feature.
-# See docs/no_sources_assignment_filter.md for more information.
-# TODO(crbug.com/1018739): remove this when migration is done.
-set_sources_assignment_filter([])
-
 source_set("input") {
   sources = [
     "client_input_injector.h",
diff --git a/rlz/BUILD.gn b/rlz/BUILD.gn
index 37247ec1e5683..a0d731800c853 100644
--- a/rlz/BUILD.gn
+++ b/rlz/BUILD.gn
@@ -8,12 +8,6 @@
 import("//rlz/buildflags/buildflags.gni")
 import("//testing/test.gni")
 
-# Reset sources_assignment_filter for the BUILD.gn file to prevent
-# regression during the migration of Chromium away from the feature.
-# See docs/no_sources_assignment_filter.md for more information.
-# TODO(crbug.com/1018739): remove this when migration is done.
-set_sources_assignment_filter([])
-
 config("rlz_lib_config") {
   defines = [ "RLZ_NETWORK_IMPLEMENTATION_CHROME_NET" ]
 }
diff --git a/sandbox/BUILD.gn b/sandbox/BUILD.gn
index fff8f927aa3d1..5bfd4d5aef9e3 100644
--- a/sandbox/BUILD.gn
+++ b/sandbox/BUILD.gn
@@ -46,7 +46,6 @@ buildflag_header("sandbox_buildflags") {
 # Although the code is Windows-based, the fuzzer is designed to work on Linux,
 # so do not disable this fuzzer on non-Windows platforms.
 fuzzer_test("sandbox_ipc_fuzzer") {
-  set_sources_assignment_filter([])
   sources = [
     "win/fuzzer/fuzzer_types.h",
     "win/fuzzer/sandbox_ipc_fuzzer.cc",
diff --git a/sandbox/win/BUILD.gn b/sandbox/win/BUILD.gn
index 7ae9c8b6cc4c0..68c1827e11236 100644
--- a/sandbox/win/BUILD.gn
+++ b/sandbox/win/BUILD.gn
@@ -367,10 +367,9 @@ shared_library("pocdll") {
   defines = [ "POCDLL_EXPORTS" ]
 }
 
-# This fuzzer will only work on Windows, add fuzz targets which could run on Linux
-# to //sandbox/ directly.
+# This fuzzer will only work on Windows, add fuzz targets which could run on
+# Linux to //sandbox/ directly.
 fuzzer_test("sandbox_policy_rule_fuzzer") {
-  set_sources_assignment_filter([])
   sources = [
     "fuzzer/fuzzer_types.h",
     "fuzzer/sandbox_policy_rule_fuzzer.cc",
diff --git a/services/data_decoder/public/cpp/BUILD.gn b/services/data_decoder/public/cpp/BUILD.gn
index 16ef9b7c14a0c..4c37a0d9591a0 100644
--- a/services/data_decoder/public/cpp/BUILD.gn
+++ b/services/data_decoder/public/cpp/BUILD.gn
@@ -22,8 +22,6 @@ component("service_provider") {
 }
 
 source_set("cpp") {
-  set_sources_assignment_filter([])
-
   public = [
     "data_decoder.h",
     "json_sanitizer.h",