Bring back relative_url_root but deprecate it

actionpack/CHANGELOG

@@ -1,5 +1,7 @@
 *2.2.3 (pending release)*
 
+* Backwards Compatibility: bring back Request#relative_url_root but deprecate it.
+
 * Rationalise the session options to one hash, prevents rack or integration tests from seeing in correct defaults. [Koz]
 
 * I18n: translate number_to_human_size. Add storage_units: [Bytes, KB, MB, GB, TB] to your translations.  #1448 [Yaroslav Markin]

actionpack/lib/action_controller/request.rb

@@ -305,6 +305,15 @@ def standard_port
         else 80
       end
     end
+
+    # Returns the value of ActionController::Base.relative_url_root.  This method is 
+    # deprecated as the value is an application wide setting, not something which
+    # changes per request.
+    def relative_url_root
+      ActiveSupport::Deprecation.warn(
+        "relative_url_root is now set application-wide, use ActionController::Base.relative_url_root instead.", caller)
+      ActionController::Base.relative_url_root
+    end
 
     # Returns a \port suffix like ":8080" if the \port number of this request
     # is not the default HTTP \port 80 or HTTPS \port 443.

actionpack/test/controller/cgi_test.rb

@@ -161,6 +161,12 @@ def test_cookie_syntax_resilience
     assert_equal ["c84ace847,96670c052c6ceb2451fb0f2"], alt_cookies["_session_id"], alt_cookies.inspect
     assert_equal ["yes"], alt_cookies["is_admin"], alt_cookies.inspect
   end
+
+  def test_relative_url_root
+    assert_deprecated("ActionController::Base.relative_url_root") do
+      assert_equal ActionController::Base.relative_url_root, @request.relative_url_root
+    end
+  end
 end
 
 class CgiRequestParamsParsingTest < BaseCgiTest