Use VulkanBrowserCompositorOS only for Aura.

content/browser/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//content/browser/browser.gni")
 import("//media/media_options.gni")
 
 source_set("browser") {
@@ skipping 442 matching lines @@
       "web_contents/web_contents_view_aura.cc",
       "web_contents/web_contents_view_aura.h",
     ]
   }
 
   if (use_aura || is_mac) {
     sources +=
         rebase_path(content_browser_gypi_values.compositor_browser_sources,
                     ".",
                     "//content")
+    if (enable_vulkan) {
+      sources += [
+        "compositor/vulkan_browser_compositor_output_surface.cc",
+        "compositor/vulkan_browser_compositor_output_surface.h",
+      ]
+    }
     if (!use_x11) {
       sources -= [
         "compositor/software_output_device_x11.cc",
         "compositor/software_output_device_x11.h",
       ]
     }
 
     if (!use_ozone) {
       sources -= [
         "compositor/browser_compositor_overlay_candidate_validator_ozone.cc",
         "compositor/browser_compositor_overlay_candidate_validator_ozone.h",
         "compositor/software_output_device_ozone.cc",
         "compositor/software_output_device_ozone.h",
       ]
     }
     deps += [ "//ui/compositor" ]
   }
 
-  if (enable_vulkan) {
-    sources += [
-      "compositor/vulkan_browser_compositor_output_surface.cc",
-      "compositor/vulkan_browser_compositor_output_surface.h",
-    ]
-  }
-
   if (enable_web_speech) {
     deps += [ "//third_party/flac" ]
   }
 
   if (is_linux && use_dbus) {
     deps += [ "//dbus" ]
   }
 
   if (enable_browser_cdms) {
     sources += [
@@ skipping 36 matching lines @@
 
 # See comment at the top of //content/BUILD.gn for how this works.
 group("for_content_tests") {
   visibility = [ "//content/test/*" ]
   if (!is_component_build) {
     public_deps = [
       ":browser",
     ]
   }
 }