Remove Chrome OS-related GN build configuration

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 366ae2e819a70af6cd01a6e89dc5184441b0b335..b39c11c439f79aec1156057f29cd554b9d2266e4 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -663,7 +663,7 @@ component("base") {
 
   # Allow more direct string conversions on platforms with native utf8
   # strings
-  if (is_mac || is_ios || is_chromeos) {
+  if (is_mac || is_ios) {
     defines = [ "SYSTEM_NATIVE_UTF8" ]
   }
 
@@ -689,10 +689,6 @@ component("base") {
     libs = [ "log" ]
   }
 
-  if (is_chromeos) {
-    sources -= [ "power_monitor/power_monitor_device_source_posix.cc" ]
-  }
-
   if (is_nacl) {
     # We reset sources_assignment_filter in order to explicitly include
     # the linux file (which would otherwise be filtered out).
@@ -896,7 +892,7 @@ component("i18n") {
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 }
 
-if (is_win || (is_linux && !is_chromeos)) {
+if (is_win || is_linux) {
   # TODO(GYP): Figure out which of these work and are needed on other platforms.
   test("base_perftests") {
     sources = [
@@ -1319,7 +1315,7 @@ test("base_unittests") {
 
   # Allow more direct string conversions on platforms with native utf8
   # strings
-  if (is_mac || is_ios || is_chromeos) {
+  if (is_mac || is_ios) {
     defines = [ "SYSTEM_NATIVE_UTF8" ]
   }