Lacros: Replace gn var is_chromeos with is_chromeos_ash.

This change is a mechanical change replacing is_chromeos with
is_chromeos_ash.

This is in preparation to switching lacros from target_os="linux" to
target_os="chromeos".

More detail on http://go/lacros-macros.

Bug: 1052397
Change-Id: I1324b2733d438d2fe62eaa54363b364ad0257862
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2628631Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Peng Huang <penghuang@chromium.org>
Commit-Queue: Yuta Hijikata <ythjkt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845496}

gpu/config/gpu_control_list.cc

@@ -276,7 +276,8 @@ bool GpuControlList::More::GLVersionInfoMismatch(
 GpuControlList::GLType GpuControlList::More::GetDefaultGLType() {
 #if BUILDFLAG(IS_CHROMEOS_ASH)
   return kGLTypeGL;
-#elif defined(OS_LINUX) || defined(OS_OPENBSD)
+#elif (defined(OS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)) || \
+    defined(OS_OPENBSD)
   return kGLTypeGL;
 #elif defined(OS_MAC)
   return kGLTypeGL;
@@ -782,7 +783,8 @@ GpuControlList::OsType GpuControlList::GetOsType() {
   return kOsAndroid;
 #elif defined(OS_FUCHSIA)
   return kOsFuchsia;
-#elif defined(OS_LINUX) || defined(OS_OPENBSD)
+#elif (defined(OS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)) || \
+    defined(OS_OPENBSD)
   return kOsLinux;
 #elif defined(OS_MAC)
   return kOsMacosx;

gpu/config/gpu_test_config.cc

@@ -28,7 +28,8 @@ namespace {
 GPUTestConfig::OS GetCurrentOS() {
 #if BUILDFLAG(IS_CHROMEOS_ASH)
   return GPUTestConfig::kOsChromeOS;
-#elif defined(OS_LINUX) || defined(OS_OPENBSD)
+#elif (defined(OS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)) || \
+    defined(OS_OPENBSD)
   return GPUTestConfig::kOsLinux;
 #elif defined(OS_WIN)
   int32_t major_version = 0;

gpu/vulkan/BUILD.gn

@@ -111,6 +111,7 @@ if (enable_vulkan) {
       ":buildflags",
       "//base",
       "//base/util/type_safety",
+      "//build:chromeos_buildflags",
       "//components/crash/core/common:crash_key",
       "//gpu/ipc/common:vulkan_ycbcr_info",
       "//ui/gfx",

gpu/vulkan/vulkan_image.cc

@@ -13,6 +13,7 @@
 #include "base/optional.h"
 #include "base/stl_util.h"
 #include "build/build_config.h"
+#include "build/chromeos_buildflags.h"
 #include "gpu/vulkan/vulkan_device_queue.h"
 #include "gpu/vulkan/vulkan_function_pointers.h"
 
@@ -320,7 +321,9 @@ bool VulkanImage::InitializeWithExternalMemory(
   };
   format_info_2.pNext = &external_info;
 
-#if defined(OS_LINUX)
+// TODO(crbug.com/1052397): Revisit once build flag switch of lacros-chrome is
+// complete.
+#if defined(OS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)
   VkPhysicalDeviceImageDrmFormatModifierInfoEXT modifier_info = {
       .sType =
           VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_IMAGE_DRM_FORMAT_MODIFIER_INFO_EXT,