diff --git a/.gn b/.gn
index 028a530ffd..5fe9f27324 100644
--- a/.gn
+++ b/.gn
@@ -16,7 +16,7 @@ no_check_targets = [
   "//:v8_internal_headers",
   "//src/inspector:inspector",
   "//test/cctest:cctest_sources",
-  "//third_party/*",
+  "//third_party/icu:*",
 ]
 
 # These are the list of GN files that run exec_script. This whitelist exists
diff --git a/third_party/google_benchmark/BUILD.gn b/third_party/google_benchmark/BUILD.gn
index 2a66bb991a..e746cc421a 100644
--- a/third_party/google_benchmark/BUILD.gn
+++ b/third_party/google_benchmark/BUILD.gn
@@ -36,7 +36,6 @@ if (v8_enable_google_benchmark) {
       "src/src/counter.cc",
       "src/src/counter.h",
       "src/src/csv_reporter.cc",
-      "src/src/cycle_clock.h",
       "src/src/internal_macros.h",
       "src/src/json_reporter.cc",
       "src/src/log.h",
diff --git a/third_party/googletest/BUILD.gn b/third_party/googletest/BUILD.gn
index 085794264f..4d393efd95 100644
--- a/third_party/googletest/BUILD.gn
+++ b/third_party/googletest/BUILD.gn
@@ -51,8 +51,6 @@ config("gmock_config") {
 source_set("gtest") {
   testonly = true
   sources = [
-    # TODO(crbug.com/829773): Remove this after transitioning off <tr1/tuple>.
-    "custom/gmock/internal/custom/gmock-port.h",
     "src/googletest/include/gtest/gtest-death-test.h",
     "src/googletest/include/gtest/gtest-matchers.h",
     "src/googletest/include/gtest/gtest-message.h",
@@ -66,12 +64,9 @@ source_set("gtest") {
     "src/googletest/include/gtest/internal/gtest-death-test-internal.h",
     "src/googletest/include/gtest/internal/gtest-filepath.h",
     "src/googletest/include/gtest/internal/gtest-internal.h",
-    "src/googletest/include/gtest/internal/gtest-linked_ptr.h",
-    "src/googletest/include/gtest/internal/gtest-param-util-generated.h",
     "src/googletest/include/gtest/internal/gtest-param-util.h",
     "src/googletest/include/gtest/internal/gtest-port.h",
     "src/googletest/include/gtest/internal/gtest-string.h",
-    "src/googletest/include/gtest/internal/gtest-tuple.h",
     "src/googletest/include/gtest/internal/gtest-type-util.h",
 
     #"src/googletest/src/gtest-all.cc",  # Not needed by our build.
@@ -129,22 +124,16 @@ source_set("gmock") {
     "src/googlemock/include/gmock/gmock-actions.h",
     "src/googlemock/include/gmock/gmock-cardinalities.h",
     "src/googlemock/include/gmock/gmock-function-mocker.h",
-    "src/googlemock/include/gmock/gmock-generated-actions.h",
-    "src/googlemock/include/gmock/gmock-generated-nice-strict.h",
     "src/googlemock/include/gmock/gmock-matchers.h",
     "src/googlemock/include/gmock/gmock-more-actions.h",
     "src/googlemock/include/gmock/gmock-more-matchers.h",
     "src/googlemock/include/gmock/gmock-nice-strict.h",
     "src/googlemock/include/gmock/gmock-spec-builders.h",
     "src/googlemock/include/gmock/gmock.h",
-    "src/googlemock/include/gmock/internal/gmock-generated-internal-utils.h",
     "src/googlemock/include/gmock/internal/gmock-internal-utils.h",
     "src/googlemock/include/gmock/internal/gmock-port.h",
     "src/googlemock/include/gmock/internal/gmock-pp.h",
 
-    # gmock helpers.
-    "custom/gmock/internal/custom/gmock-port.h",
-
     #"src/googlemock/src/gmock-all.cc",  # Not needed by our build.
     "src/googlemock/src/gmock-cardinalities.cc",
     "src/googlemock/src/gmock-internal-utils.cc",
@@ -166,6 +155,8 @@ source_set("gmock") {
     ":gmock_config",
     ":gtest_config",
   ]
+
+  deps = [ ":gtest" ]
 }
 
 # Do NOT depend on this directly. Use //testing/gmock:gmock_main instead.
@@ -173,5 +164,8 @@ source_set("gmock") {
 static_library("gmock_main") {
   testonly = true
   sources = [ "src/googlemock/src/gmock_main.cc" ]
-  deps = [ ":gmock" ]
+  deps = [
+    ":gmock",
+    ":gtest",
+  ]
 }
diff --git a/third_party/inspector_protocol/BUILD.gn b/third_party/inspector_protocol/BUILD.gn
index 880b651c09..94b7fe2677 100644
--- a/third_party/inspector_protocol/BUILD.gn
+++ b/third_party/inspector_protocol/BUILD.gn
@@ -5,7 +5,10 @@
 import("../../gni/v8.gni")
 
 config("crdtp_config") {
-  visibility = [ "../../src/inspector:*", ":*" ]
+  visibility = [
+    ":*",
+    "../../src/inspector:*",
+  ]
   configs = [ "../../:internal_config" ]
   include_dirs = [ "../../include" ]
 }
@@ -46,6 +49,7 @@ v8_source_set("crdtp_platform") {
     "crdtp/json_platform_v8.cc",
   ]
   public_deps = [ "../..:v8_libbase" ]
+  deps = [ "../../:v8_internal_headers" ]
   configs = [ ":crdtp_config" ]
 }
 
diff --git a/third_party/jsoncpp/BUILD.gn b/third_party/jsoncpp/BUILD.gn
index 411d2d62e7..6324be019c 100644
--- a/third_party/jsoncpp/BUILD.gn
+++ b/third_party/jsoncpp/BUILD.gn
@@ -21,9 +21,7 @@ source_set("jsoncpp") {
   sources = [
     "generated/version.h",
     "source/include/json/assertions.h",
-    "source/include/json/autolink.h",
     "source/include/json/config.h",
-    "source/include/json/features.h",
     "source/include/json/forwards.h",
     "source/include/json/json.h",
     "source/include/json/reader.h",