added :prefixes accessor to LookupContext.

actionpack/lib/action_view/lookup_context.rb

@@ -9,6 +9,8 @@ module ActionView
   # generate a key, given to view paths, used in the resolver cache lookup. Since
   # this key is generated just once during the request, it speeds up all cache accesses.
   class LookupContext #:nodoc:
+    attr_accessor :prefixes
+    
     mattr_accessor :fallbacks
     @@fallbacks = FallbackFileSystemResolver.instances
 

actionpack/test/template/lookup_context_test.rb

@@ -180,6 +180,12 @@ class LookupContextTest < ActiveSupport::TestCase
 
     assert_not_equal template, old_template
   end
+  
+  test "responds to #prefixes" do
+    assert_equal nil, @lookup_context.prefixes
+    @lookup_context.prefixes = ["foo"]
+    assert_equal ["foo"], @lookup_context.prefixes
+  end
 end
 
 class LookupContextWithFalseCaching < ActiveSupport::TestCase