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: Ib9e67a3cccd20549836019db36c507d71db70aa2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2494202
Commit-Queue: Yuta Hijikata <ythjkt@chromium.org>
Reviewed-by: Charlie Reis <creis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825709}

apps/BUILD.gn

@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/chromeos/ui_mode.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//extensions/buildflags/buildflags.gni")
@@ -38,6 +39,7 @@ static_library("apps") {
 
   deps = [
     "//base/util/values:values_util",
+    "//build:chromeos_buildflags",
     "//components/keyed_service/content",
     "//content/public/browser",
     "//content/public/common",
@@ -46,7 +48,7 @@ static_library("apps") {
     "//extensions/common/api",
   ]
 
-  if (is_chromeos) {
+  if (is_chromeos_ash) {
     deps += [ "//components/user_manager" ]
   }
 }

apps/app_restore_service.cc

@@ -8,6 +8,7 @@
 #include "apps/app_restore_service_factory.h"
 #include "apps/launcher.h"
 #include "apps/saved_files_service.h"
+#include "build/chromeos_buildflags.h"
 #include "content/public/browser/browser_context.h"
 #include "extensions/browser/app_window/app_window.h"
 #include "extensions/browser/extension_host.h"
@@ -26,7 +27,7 @@ namespace apps {
 // static
 bool AppRestoreService::ShouldRestoreApps(bool is_browser_restart) {
   bool should_restore_apps = is_browser_restart;
-#if defined(OS_CHROMEOS)
+#if BUILDFLAG(IS_CHROMEOS_ASH)
   // Chromeos always restarts apps, even if it was a regular shutdown.
   should_restore_apps = true;
 #endif

apps/launcher.cc

@@ -18,6 +18,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/task/task_traits.h"
 #include "base/task/thread_pool.h"
+#include "build/chromeos_buildflags.h"
 #include "components/services/app_service/public/cpp/file_handler_info.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_task_traits.h"
@@ -47,7 +48,7 @@
 #include "net/base/filename_util.h"
 #include "url/gurl.h"
 
-#if defined(OS_CHROMEOS)
+#if BUILDFLAG(IS_CHROMEOS_ASH)
 #include "components/user_manager/user_manager.h"
 #endif
 
@@ -385,7 +386,7 @@ void LaunchPlatformAppWithCommandLineAndLaunchId(
   // check in case this scenario does occur.
   if (extensions::KioskModeInfo::IsKioskOnly(app)) {
     bool in_kiosk_mode = false;
-#if defined(OS_CHROMEOS)
+#if BUILDFLAG(IS_CHROMEOS_ASH)
     user_manager::UserManager* user_manager = user_manager::UserManager::Get();
     in_kiosk_mode = user_manager && user_manager->IsLoggedInAsKioskApp();
 #endif

apps/saved_files_service.cc

@@ -14,6 +14,7 @@
 
 #include "apps/saved_files_service_factory.h"
 #include "base/util/values/values_util.h"
+#include "build/chromeos_buildflags.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/notification_service.h"
 #include "extensions/browser/api/file_system/saved_file_entry.h"
@@ -310,7 +311,7 @@ void SavedFilesService::SavedFiles::EnqueueFileEntry(const std::string& id) {
   SavedFileEntry* file_entry = it->second.get();
   int old_sequence_number = file_entry->sequence_number;
 
-#if defined(OS_CHROMEOS)
+#if BUILDFLAG(IS_CHROMEOS_ASH)
   // crbug.com/983844 Convert path from legacy Download/ to MyFiles/Downloads/
   // so entries saved before MyFiles don't fail. TODO(lucmult): Remove this
   // after M-83.

apps/ui/views/BUILD.gn

@@ -14,6 +14,7 @@ source_set("views") {
   ]
 
   deps = [
+    "//build:chromeos_buildflags",
     "//cc/paint",
     "//chrome/app/theme:theme_resources",
     "//extensions/browser",

apps/ui/views/app_window_frame_view.cc

@@ -8,6 +8,7 @@
 #include <utility>
 
 #include "base/strings/utf_string_conversions.h"
+#include "build/chromeos_buildflags.h"
 #include "cc/paint/paint_flags.h"
 #include "chrome/grit/theme_resources.h"
 #include "extensions/browser/app_window/native_app_window.h"
@@ -136,7 +137,9 @@ gfx::Rect AppWindowFrameView::GetBoundsForClientView() const {
 gfx::Rect AppWindowFrameView::GetWindowBoundsForClientBounds(
     const gfx::Rect& client_bounds) const {
   gfx::Rect window_bounds = client_bounds;
-#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+// TODO(crbug.com/1052397): Revisit once build flag switch of lacros-chrome is
+// complete.
+#if defined(OS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)
   // Get the difference between the widget's client area bounds and window
   // bounds, and grow |window_bounds| by that amount.
   gfx::Insets native_frame_insets =