Remove dependency of PrefSyncableService on PrefsTabHelper.

chrome/browser/prefs/pref_service_syncable_util.cc

Index: chrome/browser/prefs/pref_service_syncable_util.cc
diff --git a/chrome/browser/prefs/pref_service_syncable_util.cc b/chrome/browser/prefs/pref_service_syncable_util.cc
index e3b099cbc1bd585ba8046f26c1960cf232f68cc1..eac0df9b213727e2c00546322bbb833cbcc7e849 100644
--- a/chrome/browser/prefs/pref_service_syncable_util.cc
+++ b/chrome/browser/prefs/pref_service_syncable_util.cc
@@ -4,8 +4,17 @@
 
 #include "chrome/browser/prefs/pref_service_syncable_util.h"
 
+#include <vector>
+
+#include "base/logging.h"
+#include "build/build_config.h"
 #include "chrome/browser/prefs/pref_service_syncable.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/common/pref_names.h"
+
+#if defined(OS_ANDROID) || defined(OS_IOS)
+#include "components/proxy_config/proxy_config_pref_names.h"
+#endif
 
 PrefServiceSyncable* PrefServiceSyncableFromProfile(Profile* profile) {
   return static_cast<PrefServiceSyncable*>(profile->GetPrefs());
@@ -14,3 +23,19 @@ PrefServiceSyncable* PrefServiceSyncableFromProfile(Profile* profile) {
 PrefServiceSyncable* PrefServiceSyncableIncognitoFromProfile(Profile* profile) {
   return static_cast<PrefServiceSyncable*>(profile->GetOffTheRecordPrefs());
 }
+
+PrefServiceSyncable* CreateIncognitoPrefServiceSyncable(
+    PrefServiceSyncable* pref_service,
+    PrefStore* incognito_extension_pref_store) {
+  // List of keys that cannot be changed in the user prefs file by the incognito
+  // profile.  All preferences that store information about the browsing history
+  // or behavior of the user should have this property.
+  std::vector<const char*> overlay_pref_names;
+  overlay_pref_names.push_back(prefs::kBrowserWindowPlacement);
+  overlay_pref_names.push_back(prefs::kSaveFileDefaultDirectory);
+#if defined(OS_ANDROID) || defined(OS_IOS)
+  overlay_pref_names.push_back(proxy_config::prefs::kProxy);
+#endif
+  return pref_service->CreateIncognitoPrefService(
+      incognito_extension_pref_store, overlay_pref_names);
+}