[Sync] Rename syncable_prefs to sync_preferences.

Pretty mechanical CL:
- Moved files and ran mass-rename.py
- String-replaced "syncable_prefs" with "sync_preferences"
- String-replaced "SYNCABLE_PREFS_USE_POLICY" with "SYNC_PREFERENCES_USE_POLICY"
- Fixed a couple lints inside sync_preferences
- Ran formatter

BUG=659265
TBR=jam

Review-Url: https://codereview.chromium.org/2459823002
Cr-Commit-Position: refs/heads/master@{#428391}
diff --git a/chrome/browser/extensions/extension_service_unittest.cc b/chrome/browser/extensions/extension_service_unittest.cc
index e146ead..839c43d1 100644
--- a/chrome/browser/extensions/extension_service_unittest.cc
+++ b/chrome/browser/extensions/extension_service_unittest.cc
@@ -90,8 +90,8 @@
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "components/prefs/scoped_user_pref_update.h"
 #include "components/sync/model/string_ordinal.h"
-#include "components/syncable_prefs/pref_service_syncable.h"
-#include "components/syncable_prefs/testing_pref_service_syncable.h"
+#include "components/sync_preferences/pref_service_syncable.h"
+#include "components/sync_preferences/testing_pref_service_syncable.h"
 #include "content/public/browser/dom_storage_context.h"
 #include "content/public/browser/gpu_data_manager.h"
 #include "content/public/browser/indexed_db_context.h"
@@ -788,7 +788,8 @@
   }
 
   typedef extensions::ExtensionManagementPrefUpdater<
-      syncable_prefs::TestingPrefServiceSyncable> ManagementPrefUpdater;
+      sync_preferences::TestingPrefServiceSyncable>
+      ManagementPrefUpdater;
 };
 
 // Receives notifications from a PackExtensionJob, indicating either that