adding asset-data-url sass helper

Author: joenoon

README.markdown

@@ -59,6 +59,8 @@ The [list of supported options](http://sass-lang.com/docs/yardoc/file.SASS_REFER
     For example: `image_url("rails.png")` becomes `url(/assets/rails.png)` and
     `image_path("rails.png")` becomes `"/assets/rails.png"`.
 
+  * `asset_data_url($relative-asset-path)` - Returns url reference to the Base64-encoded asset at the specified path.
+    For example: `asset-data-url("rails.png")` becomes `url(data:image/png;base64,iVBORw0K...)`
 
 ## Running Tests
 

lib/sass/rails/helpers.rb

@@ -2,6 +2,11 @@ module Sass
   module Rails
     module Helpers
 
+      def asset_data_url(path)
+        data = context_asset_data_uri(path.value)
+        Sass::Script::String.new(%Q{url(#{data})})
+      end
+
       def asset_path(asset, kind)
         Sass::Script::String.new(public_path(asset.value, kind.value), true)
       end
@@ -25,6 +30,10 @@ def #{asset_class}_url(asset)
       def public_path(asset, kind)
         options[:custom][:resolver].public_path(asset, kind.pluralize)
       end
+      
+      def context_asset_data_uri(path)
+        options[:custom][:resolver].context.asset_data_uri(path)
+      end
     end
   end
 end