Use SkLayerDrawLooper::Builder to construct SkLayerDrawLooper.

Source/platform/graphics/DrawLooperBuilder.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 10 matching lines @@
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * 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
+#ifndef DrawLooperBuilder_h
+#define DrawLooperBuilder_h
 
 #include "platform/PlatformExport.h"
+#include "third_party/skia/include/effects/SkLayerDrawLooper.h"
 #include "wtf/Noncopyable.h"
-#include "wtf/RefPtr.h"
+#include "wtf/PassOwnPtr.h"
+#include "wtf/PassRefPtr.h"
 
 class SkDrawLooper;
-class SkLayerDrawLooper;
 
 namespace WebCore {
 
 class Color;
 class FloatSize;
 
-class PLATFORM_EXPORT DrawLooper {
+class PLATFORM_EXPORT DrawLooperBuilder FINAL {
     // Implementing the copy constructor properly would require writing code to
-    // copy the underlying SkDrawLooper.
-    WTF_MAKE_NONCOPYABLE(DrawLooper);
+    // copy the underlying SkLayerDrawLooper::Builder.
+    WTF_MAKE_NONCOPYABLE(DrawLooperBuilder);
 
 public:
     enum ShadowTransformMode {
         ShadowRespectsTransforms,
         ShadowIgnoresTransforms
     };
     enum ShadowAlphaMode {
         ShadowRespectsAlpha,
         ShadowIgnoresAlpha
     };
 
-    DrawLooper();
-    ~DrawLooper();
+    DrawLooperBuilder();
+    ~DrawLooperBuilder();
 
-    // 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;
+    static PassOwnPtr<DrawLooperBuilder> create();
+
+    // Creates the SkDrawLooper and passes ownership to the caller. The builder
+    // should not be used any more after calling this method.
+    PassRefPtr<SkDrawLooper> detachDrawLooper();
 
     void addUnmodifiedContent();
     void addShadow(const FloatSize& offset, float blur, const Color&,
         ShadowTransformMode = ShadowRespectsTransforms,
         ShadowAlphaMode = ShadowRespectsAlpha);
 
 private:
-    RefPtr<SkLayerDrawLooper> m_skDrawLooper;
+    SkLayerDrawLooper::Builder m_skDrawLooperBuilder;
 };
 
 } // namespace WebCore
 
-#endif // DrawLooper_h
+#endif // DrawLooperBuilder_h