LaCrOS: Replace defined(OS_CHROMEOS) with BUILDFLAG(IS_CHROMEOS_ASH)

The change is mostly mechanical replacing defined(OS_CHROMEOS) with
BUILDFLAG(IS_CHROMEOS_ASH) and GN variable is_chromeos with is_ash
with some special cases (For those cases please refer to
http://go/lacros-macros).

The patch is made in preparation to switching lacros build from
target_os=linux to target_os=chromeos. This will prevent lacros from
changing behaviour after the switch.

Bug: 1052397
Change-Id: Ibe63a58f20c536f639c7d5af640df4f37ce460c0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2494280
Commit-Queue: Yuta Hijikata <ythjkt@chromium.org>
Reviewed-by: Charlie Reis <creis@chromium.org>
Reviewed-by: Eric Seckler <eseckler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828629}

headless/BUILD.gn

@@ -403,6 +403,7 @@ component("headless_non_renderer") {
     ":headless_shared_sources",
     ":version_header",
     "//base:base_static",
+    "//build:chromeos_buildflags",
     "//components/cookie_config",
     "//components/security_state/core",
     "//content/public/common",

headless/lib/browser/headless_browser_main_parts_linux.cc

@@ -5,12 +5,13 @@
 #include "headless/lib/browser/headless_browser_main_parts.h"
 
 #include "build/build_config.h"
+#include "build/chromeos_buildflags.h"
 #include "device/bluetooth/dbus/bluez_dbus_manager.h"
 
 namespace headless {
 
 void HeadlessBrowserMainParts::PostMainMessageLoopStart() {
-#if defined(USE_DBUS) && !defined(OS_CHROMEOS)
+#if defined(USE_DBUS) && !BUILDFLAG(IS_CHROMEOS_ASH)
   bluez::BluezDBusManager::Initialize(/*system_bus=*/nullptr);
 #endif
 }

headless/lib/browser/headless_request_context_manager.cc

@@ -8,6 +8,7 @@
 #include "base/task/post_task.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
+#include "build/chromeos_buildflags.h"
 #include "content/public/browser/browser_task_traits.h"
 #include "content/public/browser/network_service_instance.h"
 #include "content/public/browser/resource_context.h"
@@ -26,7 +27,9 @@ namespace headless {
 
 namespace {
 
-#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+// TODO(crbug.com/1052397): Revisit the macro expression once build flag switch
+// of lacros-chrome is complete.
+#if defined(OS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)
 constexpr char kProductName[] = "HeadlessChrome";
 #endif
 
@@ -56,7 +59,9 @@ net::NetworkTrafficAnnotationTag GetProxyConfigTrafficAnnotationTag() {
   return traffic_annotation;
 }
 
-#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+// TODO(crbug.com/1052397): Revisit the macro expression once build flag switch
+// of lacros-chrome is complete.
+#if defined(OS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)
 ::network::mojom::CryptConfigPtr BuildCryptConfigOnce(
     const base::FilePath& user_data_path) {
   static bool done_once = false;
@@ -218,7 +223,9 @@ HeadlessRequestContextManager::HeadlessRequestContextManager(
           base::ThreadTaskRunnerHandle::Get());
     }
   }
-#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+// TODO(crbug.com/1052397): Revisit the macro expression once build flag switch
+// of lacros-chrome is complete.
+#if defined(OS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)
   auto crypt_config = BuildCryptConfigOnce(user_data_path_);
   if (crypt_config)
     content::GetNetworkService()->SetCryptConfig(std::move(crypt_config));