Clean up deprecated sources assignment filter in //content/gpu

Remove deprecated_default_sources_assignment_filter and replace
it with explicit is_win, is_mac, etc. sections.

Bug: 1018739
Change-Id: I0cb37ff563d65cc981e368e6ba1c5731f1ae6250
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2445612Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813683}

content/gpu/BUILD.gn

@@ -6,13 +6,6 @@ import("//build/config/ui.gni")
 import("//gpu/vulkan/features.gni")
 import("//media/media_options.gni")
 
-# This file depends on the legacy global sources assignment filter. It should
-# be converted to check target platform before assigning source files to the
-# sources variable. Remove this import and set_sources_assignment_filter call
-# when the file has been converted. See https://crbug.com/1018739 for details.
-import("//build/config/deprecated_default_sources_assignment_filter.gni")
-set_sources_assignment_filter(deprecated_default_sources_assignment_filter)
-
 # See //content/BUILD.gn for how this works.
 group("gpu") {
   visibility = [ "//content/*" ]  # This is an internal content API.
@@ -44,8 +37,6 @@ target(link_target_type, "gpu_sources") {
     "gpu_main.cc",
     "gpu_process.cc",
     "gpu_process.h",
-    "gpu_sandbox_hook_linux.cc",
-    "gpu_sandbox_hook_linux.h",
     "gpu_service_factory.cc",
     "gpu_service_factory.h",
     "in_process_gpu_thread.cc",
@@ -93,6 +84,13 @@ target(link_target_type, "gpu_sources") {
     "//ui/latency/ipc",
   ]
 
+  if (is_linux || is_chromeos) {
+    sources += [
+      "gpu_sandbox_hook_linux.cc",
+      "gpu_sandbox_hook_linux.h",
+    ]
+  }
+
   if (is_android) {
     deps += [
       "//components/tracing:graphics_provider",