Remove dead StyleRuleFilter.

sky/engine/core/css/StyleRule.cpp

Index: sky/engine/core/css/StyleRule.cpp
diff --git a/sky/engine/core/css/StyleRule.cpp b/sky/engine/core/css/StyleRule.cpp
index 66777ea721f79fa027c71124f8d3432a980f1128..7e3adfc084961b272ce6cf497db97e4223cd8a7b 100644
--- a/sky/engine/core/css/StyleRule.cpp
+++ b/sky/engine/core/css/StyleRule.cpp
@@ -51,9 +51,6 @@ void StyleRuleBase::destroy()
     case Keyframes:
         delete toStyleRuleKeyframes(this);
         return;
-    case Filter:
-        delete toStyleRuleFilter(this);
-        return;
     case Unknown:
     case Keyframe:
         ASSERT_NOT_REACHED();
@@ -114,19 +111,4 @@ StyleRuleSupports::StyleRuleSupports(const String& conditionText, bool condition
 {
 }
 
-StyleRuleFilter::StyleRuleFilter(const String& filterName)
-    : StyleRuleBase(Filter)
-    , m_filterName(filterName)
-{
-}
-
-StyleRuleFilter::~StyleRuleFilter()
-{
-}
-
-void StyleRuleFilter::setProperties(PassRefPtr<StylePropertySet> properties)
-{
-    m_properties = properties;
-}
-
 } // namespace blink