Remove non-cros support from ash/common/system.

ash/common/system/system_notifier.cc

Index: ash/common/system/system_notifier.cc
diff --git a/ash/common/system/system_notifier.cc b/ash/common/system/system_notifier.cc
index f014d805026c8bd08fad9ade0d324f4abe98c925..8150e7882a2b13a78625ff64a9a0a5ea0dd90800 100644
--- a/ash/common/system/system_notifier.cc
+++ b/ash/common/system/system_notifier.cc
@@ -20,9 +20,7 @@ namespace {
 const char* kAlwaysShownSystemNotifierIds[] = {
     kNotifierAccessibility, kNotifierDeprecatedAccelerator, kNotifierBattery,
     kNotifierDisplay, kNotifierDisplayError,
-#if defined(OS_CHROMEOS)
     kNotifierNetworkError,
-#endif
     kNotifierPower,
     // Note: Order doesn't matter here, so keep this in alphabetic order, don't
     // just add your stuff at the end!
@@ -31,14 +29,8 @@ const char* kAlwaysShownSystemNotifierIds[] = {
 // |kAshSystemNotifiers| is the list of normal system notification sources for
 // ash events. These notifications can be hidden in some context.
 const char* kAshSystemNotifiers[] = {
-    kNotifierBluetooth, kNotifierDisplayResolutionChange,
-#if defined(OS_CHROMEOS)
-    kNotifierDisk,
-#endif
-    kNotifierLocale, kNotifierMultiProfileFirstRun,
-#if defined(OS_CHROMEOS)
-    kNotifierNetwork,
-#endif
+    kNotifierBluetooth, kNotifierDisplayResolutionChange, kNotifierDisk,
+    kNotifierLocale, kNotifierMultiProfileFirstRun, kNotifierNetwork,
     kNotifierNetworkPortalDetector, kNotifierScreenshot, kNotifierScreenCapture,
     kNotifierScreenShare, kNotifierSessionLengthTimeout,
     kNotifierSupervisedUser, kNotifierWebUsb,