Use SkLayerDrawLooper::Builder to construct SkLayerDrawLooper.

Source/platform/graphics/DrawLooper.h

 /*
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 14 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef DrawLooper_h
 #define DrawLooper_h
 
 #include "platform/PlatformExport.h"
+#include "third_party/skia/include/effects/SkLayerDrawLooper.h"
 #include "wtf/Noncopyable.h"
-#include "wtf/RefPtr.h"
+#include "wtf/OwnPtr.h"
+#include "wtf/PassOwnPtr.h"
 
 class SkDrawLooper;
-class SkLayerDrawLooper;
 
 namespace WebCore {
 
 class Color;
 class FloatSize;
 
 class PLATFORM_EXPORT DrawLooper {
     // Implementing the copy constructor properly would require writing code to
     // copy the underlying SkDrawLooper.
     WTF_MAKE_NONCOPYABLE(DrawLooper);
 
 public:
     enum ShadowTransformMode {
         ShadowRespectsTransforms,
         ShadowIgnoresTransforms
     };
     enum ShadowAlphaMode {
         ShadowRespectsAlpha,
         ShadowIgnoresAlpha
     };
 
-    DrawLooper();
     ~DrawLooper();
 
     // Callees should not modify this looper other than to iterate over it.
     // A downcast to SkLayerDrawLooper* is tantamount to a const_cast.
     SkDrawLooper* skDrawLooper() const;
 
-    void addUnmodifiedContent();
-    void addShadow(const FloatSize& offset, float blur, const Color&,
-        ShadowTransformMode = ShadowRespectsTransforms,
-        ShadowAlphaMode = ShadowRespectsAlpha);
+    class Builder {
+    public:
+        Builder() { }
+        ~Builder() { }
+
+        void addUnmodifiedContent();
+        void addShadow(const FloatSize& offset, float blur, const Color&,
+            ShadowTransformMode = ShadowRespectsTransforms,
+            ShadowAlphaMode = ShadowRespectsAlpha);
+
+        // Pass layers to new DrawLooper object and return it. The builder
+        // should not be used any more after calling this method.
+        PassOwnPtr<DrawLooper> detachDrawLooper();
+
+    private:
+        SkLayerDrawLooper::Builder m_skDrawLooperBuilder;
+    };
 
 private:
-    RefPtr<SkLayerDrawLooper> m_skDrawLooper;
+    DrawLooper(PassOwnPtr<SkDrawLooper>);
+    OwnPtr<SkDrawLooper> m_skDrawLooper;

[jbroman, 2014/02/24 18:53:38]

I'm sorry I wasn't clear enough before, but while WebCore::DrawLooper is now not
refcounted (and so can be held with an OwnPtr), SkDrawLooper is still refcounted
(so it should be held with RefPtr here, and the constructor argument should be a
PassRefPtr).

[Dominik Grewe, 2014/02/24 19:41:03]

Of course, sorry. Wasn't thinking properly ;) Will fix it tomorrow.

 };
 
 } // namespace WebCore
 
 #endif // DrawLooper_h