Refactoring DrawLooper so that it can apply shadow effects as skia image filters

Source/core/rendering/InlineTextBox.cpp

Index: Source/core/rendering/InlineTextBox.cpp
diff --git a/Source/core/rendering/InlineTextBox.cpp b/Source/core/rendering/InlineTextBox.cpp
index 2bfe7de7bd567c9e49c226ef29d52ea77c0c14fd..bf9ab04b82862c21e74a39359f6d6b1a936d9109 100644
--- a/Source/core/rendering/InlineTextBox.cpp
+++ b/Source/core/rendering/InlineTextBox.cpp
@@ -396,17 +396,17 @@ static void paintTextWithShadows(GraphicsContext* context,
     Color fillColor = context->fillColor();
 
     if (hasShadow) {
-        DrawLooper drawLooper;
+        RefPtr<DrawLooper> drawLooper(new DrawLooper);
         do {
             int shadowX = horizontal ? shadow->x() : shadow->y();
             int shadowY = horizontal ? shadow->y() : -shadow->x();
             FloatSize offset(shadowX, shadowY);
-            drawLooper.addShadow(offset, shadow->blur(),
+            drawLooper->addShadow(offset, shadow->blur(),
                 renderer->resolveColor(shadow->color(), Color::stdShadowColor),
                 DrawLooper::ShadowRespectsTransforms, DrawLooper::ShadowIgnoresAlpha);
         } while ((shadow = shadow->next()));
-        drawLooper.addUnmodifiedContent();
-        context->setDrawLooper(drawLooper);
+        drawLooper->addUnmodifiedContent();
+        context->setDrawLooper(drawLooper.release());
     }
 
     TextRunPaintInfo textRunPaintInfo(textRun);