Fix unresolved string extension dependencies

activesupport/lib/active_support/multibyte/chars.rb

 # encoding: utf-8
+require 'active_support/core_ext/string/access'
 require 'active_support/core_ext/string/behavior'
 
 module ActiveSupport #:nodoc:
@@ -197,7 +198,7 @@ def include?(other)
       #   'Café périferôl'.mb_chars.index('ô') #=> 12
       #   'Café périferôl'.mb_chars.index(/\w/u) #=> 0
       def index(needle, offset=0)
-        wrapped_offset = self.first(offset).wrapped_string.length
+        wrapped_offset = first(offset).wrapped_string.length
         index = @wrapped_string.index(needle, wrapped_offset)
         index ? (self.class.u_unpack(@wrapped_string.slice(0...index)).size) : nil
       end
@@ -211,7 +212,7 @@ def index(needle, offset=0)
       #   'Café périferôl'.mb_chars.rindex(/\w/u) #=> 13
       def rindex(needle, offset=nil)
         offset ||= length
-        wrapped_offset = self.first(offset).wrapped_string.length
+        wrapped_offset = first(offset).wrapped_string.length
         index = @wrapped_string.rindex(needle, wrapped_offset)
         index ? (self.class.u_unpack(@wrapped_string.slice(0...index)).size) : nil
       end

activesupport/lib/active_support/values/time_zone.rb

+require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/time'
 require 'active_support/core_ext/date'
 require 'active_support/core_ext/date_time'