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

Source/core/platform/graphics/GraphicsContext.cpp

 /*
  * Copyright (C) 2003, 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 264 matching lines @@
     DrawLooper::ShadowAlphaMode shadowAlphaMode)
 {
     if (paintingDisabled())
         return;
 
     if (!color.alpha() || (!offset.width() && !offset.height() && !blur)) {
         clearShadow();
         return;
     }
 
-    DrawLooper drawLooper;
-    drawLooper.addShadow(offset, blur, color, shadowTransformMode, shadowAlphaMode);
-    drawLooper.addUnmodifiedContent();
-    setDrawLooper(drawLooper);
+    RefPtr<DrawLooper> drawLooper = adoptRef(new DrawLooper);
+    drawLooper->addShadow(offset, blur, color, shadowTransformMode, shadowAlphaMode);
+    drawLooper->addUnmodifiedContent();
+    setDrawLooper(drawLooper.release());
 }
 
-void GraphicsContext::setDrawLooper(const DrawLooper& drawLooper)
+void GraphicsContext::setDrawLooper(PassRefPtr<DrawLooper> drawLooper)
 {
     if (paintingDisabled())
         return;
 
-    m_state->m_looper = drawLooper.skDrawLooper();
+    m_state->m_looper = drawLooper;
 }
 
 void GraphicsContext::clearDrawLooper()
 {
     if (paintingDisabled())
         return;
 
     m_state->m_looper.clear();
 }
 
@@ skipping 324 matching lines @@
     save();
     if (rect.isRounded()) {
         Path path;
         path.addRoundedRect(rect);
         clipPath(path);
         roundedHole.shrinkRadii(shadowSpread);
     } else {
         clip(rect.rect());
     }
 
-    DrawLooper drawLooper;
-    drawLooper.addShadow(shadowOffset, shadowBlur, shadowColor,
+    RefPtr<DrawLooper> drawLooper = adoptRef(new DrawLooper);
+    drawLooper->addShadow(shadowOffset, shadowBlur, shadowColor,
         DrawLooper::ShadowRespectsTransforms, DrawLooper::ShadowIgnoresAlpha);
     setDrawLooper(drawLooper);
     fillRectWithRoundedHole(outerRect, roundedHole, fillColor);
     restore();
     clearDrawLooper();
 }
 
 // This is only used to draw borders.
 void GraphicsContext::drawLine(const IntPoint& point1, const IntPoint& point2)
 {
@@ skipping 1058 matching lines @@
 {
 #if defined(SK_DEBUG)
     {
         SkPaint defaultPaint;
         SkASSERT(*paint == defaultPaint);
     }
 #endif
 
     paint->setAntiAlias(m_state->m_shouldAntialias);
     paint->setXfermodeMode(m_state->m_xferMode);
-    paint->setLooper(m_state->m_looper.get());
+    paint->setLooper(m_state->m_looper ? m_state->m_looper->skDrawLooper() : 0);
 }
 
 void GraphicsContext::drawOuterPath(const SkPath& path, SkPaint& paint, int width)
 {
 #if OS(DARWIN)
     paint.setAlpha(64);
     paint.setStrokeWidth(width);
     paint.setPathEffect(new SkCornerPathEffect((width - 1) * 0.5f))->unref();
 #else
     paint.setStrokeWidth(1);
@@ skipping 157 matching lines @@
 
 void GraphicsContext::didDrawTextInRect(const SkRect& textRect)
 {
     if (m_trackTextRegion) {
         TRACE_EVENT0("skia", "PlatformContextSkia::trackTextRegion");
         m_textRegion.join(textRect);
     }
 }
 
 }