Revert of gn: Remove unnecessary v8 defaults (patchset #7 id:120001 of...

Revert of gn: Remove unnecessary v8 defaults (patchset #7 id:120001 of https://codereview.chromium.org/2058033002/ )

Reason for revert:
Seems to have broken Google Chrome Mac builder:
/b/c/b/Google_Chrome_Mac/src/buildtools/mac/gn gen //out/Release --check
  -> returned 1
ERROR at //chrome/BUILD.gn:514:7: Replacing nonempty list.
      remove_configs = [ "//build/config/mac:strip_all" ]
      ^-------------
This overwrites a previously-defined nonempty list (length 2).
See //v8/gni/v8.gni:55:3: for previous definition
  remove_configs += [ "//build/config/compiler:default_optimization" ]
  ^------------------------------------------------------------------
with another one (length 1). Did you mean "+=" to append instead? If you
really want to do this, do
  remove_configs = []
before reassigning.
See //BUILD.gn:202:7: which caused the file to be included.
      "//chrome",
      ^---------
GN gen failed: 1

Original issue's description:
> gn: Remove unnecessary v8 defaults
>
> Remove chromium defaults for v8_optimized_debug and
> v8_use_external_startup_data.
>
> This is not needed after v8 provides these defaults:
> https://codereview.chromium.org/2025803003/
> https://codereview.chromium.org/2024833002/
>
> It also interferes if somebody tries to override the gn args
> with a different value.
>
> BUG=chromium:616034
> TBR=alokp@chromium.org, brettw@chromium.org
>
> Committed: https://crrev.com/0fffeb2adaa3c284b760922c1aecce1516b998ce
> Cr-Commit-Position: refs/heads/master@{#406067}

TBR=jochen@chromium.org,dpranke@chromium.org,vogelheim@chromium.org,alokp@chromium.org,brettw@chromium.org,machenbach@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:616034

Review-Url: https://codereview.chromium.org/2160663003
Cr-Commit-Position: refs/heads/master@{#406072}

BUILD.gn

@@ -16,7 +16,6 @@ import("//build_overrides/v8.gni")
 import("//media/media_options.gni")
 import("//third_party/openh264/openh264_args.gni")
 import("//tools/ipc_fuzzer/ipc_fuzzer.gni")
-import("//v8/gni/v8.gni")
 import("//v8/snapshot_toolchain.gni")
 
 if (is_android) {

build_overrides/v8.gni

@@ -9,6 +9,11 @@ if (is_android) {
 # TODO(sky): nuke this. Temporary while sorting out http://crbug.com/465456.
 enable_correct_v8_arch = false
 
+v8_use_external_startup_data = !is_ios
+
+# Turns on compiler optimizations in V8 in Debug build.
+v8_optimized_debug = true
+
 # V8 extras
 # Adding V8 extras files requires API owners review
 # Be sure to synchronize with build/common.gypi

chrome/BUILD.gn

@@ -15,7 +15,6 @@ import("//chrome/chrome_repack_locales.gni")
 import("//chrome/common/features.gni")
 import("//chrome/version.gni")
 import("//ui/base/ui_features.gni")
-import("//v8/gni/v8.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")

chrome/installer/mini_installer/BUILD.gn

@@ -6,11 +6,11 @@ import("//build/config/compiler/compiler.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/config/win/visual_studio_version.gni")
+import("//build_overrides/v8.gni")
 import("//chrome/test/mini_installer/mini_installer_test.gni")
 import("//chrome/version.gni")
 import("//third_party/icu/config.gni")
 import("//ui/base/ui_features.gni")
-import("//v8/gni/v8.gni")
 
 config("mini_installer_compiler_flags") {
   # Disable buffer security checking.

chrome/test/BUILD.gn

@@ -11,7 +11,6 @@ import("//chrome/chrome_tests.gni")
 import("//chrome/common/features.gni")
 import("//chrome/test/base/js2gtest.gni")
 import("//testing/test.gni")
-import("//v8/gni/v8.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")

chrome/test/base/js2gtest.gni

@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//v8/gni/v8.gni")
+import("//build_overrides/v8.gni")
 import("//v8/snapshot_toolchain.gni")
 
 # Variables:

chromecast/BUILD.gn

@@ -6,12 +6,12 @@ import("//build/buildflag_header.gni")
 import("//build/config/features.gni")
 import("//build/config/locales.gni")
 import("//build/config/ui.gni")
+import("//build_overrides/v8.gni")
 import("//chromecast/build/tests/cast_test.gni")
 import("//chromecast/chromecast.gni")
 import("//media/media_options.gni")
 import("//tools/grit/repack.gni")
 import("//ui/ozone/ozone.gni")
-import("//v8/gni/v8.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")

content/shell/BUILD.gn

@@ -15,8 +15,8 @@ if (is_android) {
   import("//build/config/android/config.gni")
 } else if (is_mac) {
   import("//build/config/mac/rules.gni")
+  import("//build_overrides/v8.gni")
   import("//build/mac/tweak_info_plist.gni")
-  import("//v8/gni/v8.gni")
 } else if (is_win) {
   import("//build/win/syzygy/syzygy.gni")
 }

content/test/BUILD.gn

@@ -7,10 +7,10 @@ import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
+import("//build_overrides/v8.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 import("//testing/test.gni")
-import("//v8/gni/v8.gni")
 
 content_tests_gypi_values =
     exec_script("//build/gypi_to_gn.py",

gin/BUILD.gn

@@ -2,8 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build_overrides/v8.gni")
 import("//testing/test.gni")
-import("//v8/gni/v8.gni")
 
 component("gin") {
   sources = [

net/BUILD.gn

@@ -8,13 +8,13 @@ import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
+import("//build_overrides/v8.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 import("//testing/test.gni")
 import("//third_party/icu/config.gni")
 import("//third_party/protobuf/proto_library.gni")
 import("//tools/grit/grit_rule.gni")
 import("//url/features.gni")
-import("//v8/gni/v8.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")