Fix @Keyframes parsing in CSS.

Closes #1657

doc-src/SASS_CHANGELOG.md

@@ -7,6 +7,8 @@
 
 * Be clearer in the reference about hyphen/underscore equivalence.
 
+* `@keyframes` rules are now converted from CSS properly.
+
 ## 3.4.12 (13 February 2015)
 
 [Tagged on GitHub](https://github.com/sass/sass/releases/tag/3.4.12).

lib/sass/scss/css_parser.rb

@@ -14,6 +14,13 @@ def parent_selector; nil; end
       def interpolation(warn_for_color = false); nil; end
       def use_css_import?; true; end
 
+      def block_contents(node, context)
+        if node.is_a?(Sass::Tree::DirectiveNode) && node.normalized_name == '@keyframes'
+          context = :keyframes
+        end
+        super(node, context)
+      end
+
       def block_child(context)
         case context
         when :ruleset
@@ -22,6 +29,8 @@ def block_child(context)
           directive || ruleset
         when :directive
           directive || declaration_or_ruleset
+        when :keyframes
+          keyframes_ruleset
         end
       end
 
@@ -35,6 +44,12 @@ def ruleset
         block(node(Sass::Tree::RuleNode.new(selector, range(start_pos)), start_pos), :ruleset)
       end
 
+      def keyframes_ruleset
+        start_pos = source_position
+        return unless (selector = keyframes_selector)
+        block(node(Sass::Tree::KeyframeRuleNode.new(selector.strip), start_pos), :ruleset)
+      end
+
       @sass_script_parser = Class.new(Sass::Script::CssParser)
       @sass_script_parser.send(:include, ScriptParser)
     end

lib/sass/tree/visitors/convert.rb

@@ -280,6 +280,10 @@ def visit_atroot(node)
     end
   end
 
+  def visit_keyframerule(node)
+    "#{tab_str}#{node.resolved_value}#{yield}\n"
+  end
+
   private
 
   def interp_to_src(interp)

test/sass/css2sass_test.rb

@@ -263,6 +263,38 @@ def test_subject
 CSS
   end
 
+  def test_keyframes
+    assert_equal(<<SASS, css2sass(<<CSS))
+@keyframes dash
+  from
+    stroke-dasharray: 1,200
+    stroke-dashoffset: 0
+
+  50%
+    stroke-dasharray: 89,200
+    stroke-dashoffset: -35
+
+  to
+    stroke-dasharray: 89,200
+    stroke-dashoffset: -124
+SASS
+@keyframes dash {
+  from {
+    stroke-dasharray: 1,200;
+    stroke-dashoffset: 0;
+  }
+  50% {
+    stroke-dasharray: 89,200;
+    stroke-dashoffset: -35;
+  }
+  to {
+    stroke-dasharray: 89,200;
+    stroke-dashoffset: -124;
+  }
+}
+CSS
+  end
+
   # Regressions
 
   def test_nesting_with_matching_property