Add settings for keyboard auto-repeat to options page.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 570f1dd8846a41650bf107671fba4cc0a8813de6..58975cbd3c1bd4498f36700705798f39161c0dd4 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -566,8 +566,10 @@ const char kLanguageXkbAutoRepeatDelay[] =
 // A integer pref which determines key repeat interval (in ms).
 const char kLanguageXkbAutoRepeatInterval[] =
     "settings.language.xkb_auto_repeat_interval_r2";
-// "_r2" suffixes are added to the three prefs above when we change the
-// preferences not user-configurable, not to sync them with cloud.
+// "_r2" suffixes were added to the three prefs above when we changed the
+// preferences to not be user-configurable or sync with the cloud. The prefs are
+// now user-configurable and syncable again, but we don't want to overwrite the
+// current values with the old synced values, so we continue to use this suffix.
 
 // A boolean pref which determines whether the large cursor feature is enabled.
 const char kAccessibilityLargeCursorEnabled[] =