Remove the migration code from content_settings::DefaultProvider.

components/content_settings/core/common/pref_names.cc

Index: components/content_settings/core/common/pref_names.cc
diff --git a/components/content_settings/core/common/pref_names.cc b/components/content_settings/core/common/pref_names.cc
index 71818e2c1eb3c3ca2e2787af97a4ee6fb3f7e008..4c0ffb2be046ed13d01f28705466e2dde8c41416 100644
--- a/components/content_settings/core/common/pref_names.cc
+++ b/components/content_settings/core/common/pref_names.cc
@@ -24,15 +24,6 @@ const char kContentSettingsPatternPairs[] =
 const char kContentSettingsWindowLastTabIndex[] =
     "content_settings_window.last_tab_index";
 
-// Dictionary of content settings applied to all hosts by default.
-// TODO(msramek): Deprecated. Use the individual preferences below.
-const char kDefaultContentSettings[] = "profile.default_content_settings";
-
-// Whether |kDefaultContentSettings| has already been migrated to
-// |kDefault<type>Setting| prefs.
-const char kMigratedDefaultContentSettings[] =
-    "profile.migrated_default_content_settings";
-
 // Preferences storing the default values for individual content settings.
 const char kDefaultCookiesSetting[] =
     "profile.default_content_setting_values.cookies";