Linux Aura: Use system title bar is now set by preference, not flag.

chrome/browser/ui/browser_view_prefs.cc

Index: chrome/browser/ui/browser_view_prefs.cc
diff --git a/chrome/browser/ui/browser_view_prefs.cc b/chrome/browser/ui/browser_view_prefs.cc
index 0f6ea9484090077ad6e422c273e339b202ff3dad..880afda67eea8a88f3f8c298d332fba6798bb33b 100644
--- a/chrome/browser/ui/browser_view_prefs.cc
+++ b/chrome/browser/ui/browser_view_prefs.cc
@@ -6,6 +6,7 @@
 
 #include "base/prefs/pref_registry_simple.h"
 #include "chrome/common/pref_names.h"
+#include "components/user_prefs/pref_registry_syncable.h"
 
 namespace {
 
@@ -26,4 +27,16 @@ void RegisterBrowserViewPrefs(PrefRegistrySimple* registry) {
                                 kDefaultHungPluginDetectFrequency);
 }
 
+void RegisterBrowserViewSyncablePrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+  // TODO(mgiuca): Decide on this default depending on the window manager. See
+  // BrowserWindowGtk::GetCustomFramePrefDefault.
+  bool custom_frame_default = true;
+
+  registry->RegisterBooleanPref(
+      prefs::kUseCustomChromeFrame,
+      custom_frame_default,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+}
+
 }  // namespace chrome