Clean up deprecated sources assignment filter in //base

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

Bug: 1018739
Change-Id: Id609bfd6a418bac9ba1b3cc02f1a65b7aeffea28
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2442834Reviewed-by: Will Harris <wfh@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813108}

base/allocator/BUILD.gn

@@ -6,13 +6,6 @@ import("//base/allocator/allocator.gni")
 import("//build/buildflag_header.gni")
 import("//build/config/compiler/compiler.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)
-
 declare_args() {
   # Provide a way to force disable debugallocation in Debug builds,
   # e.g. for profiling (it's more rare to profile Debug builds,
@@ -95,9 +88,6 @@ if (use_allocator == "tcmalloc") {
       # Generated for our configuration from tcmalloc's build
       # and checked in.
       "$tcmalloc_dir/src/config.h",
-      "$tcmalloc_dir/src/config_android.h",
-      "$tcmalloc_dir/src/config_linux.h",
-      "$tcmalloc_dir/src/config_win.h",
 
       # tcmalloc native and forked files.
       "$tcmalloc_dir/src/base/abort.cc",
@@ -186,6 +176,18 @@ if (use_allocator == "tcmalloc") {
       #"win_allocator.cc",
     ]
 
+    if (is_android) {
+      sources += [ "$tcmalloc_dir/src/config_android.h" ]
+    }
+
+    if (is_linux || is_chromeos) {
+      sources += [ "$tcmalloc_dir/src/config_linux.h" ]
+    }
+
+    if (is_win) {
+      sources += [ "$tcmalloc_dir/src/config_win.h" ]
+    }
+
     # Not included on mips64el.
     if (current_cpu == "mips64el") {
       sources -= [