Refactor WebCore::DragImage.

Source/core/platform/chromium/ClipboardChromium.cpp

Index: Source/core/platform/chromium/ClipboardChromium.cpp
diff --git a/Source/core/platform/chromium/ClipboardChromium.cpp b/Source/core/platform/chromium/ClipboardChromium.cpp
index 363d378ad124d89615cb85a3ca4decb7fbbc183d..2e2dbab0734267c4c8ce42198542565525cf9371 100644
--- a/Source/core/platform/chromium/ClipboardChromium.cpp
+++ b/Source/core/platform/chromium/ClipboardChromium.cpp
@@ -323,19 +323,18 @@ void ClipboardChromium::setDragImageElement(Node* node, const IntPoint& loc)
     setDragImage(0, node, loc);
 }
 
-DragImageRef ClipboardChromium::createDragImage(IntPoint& loc) const
+PassOwnPtr<DragImage> ClipboardChromium::createDragImage(IntPoint& loc) const
 {
-    DragImageRef result = 0;
     if (m_dragImageElement) {
         if (m_frame) {
-            result = m_frame->nodeImage(m_dragImageElement.get());
             loc = m_dragLoc;
+            return m_frame->nodeImage(m_dragImageElement.get());
         }
     } else if (m_dragImage) {
-        result = createDragImageFromImage(m_dragImage->image());
         loc = m_dragLoc;
+        return DragImage::create(m_dragImage->image());
     }
-    return result;
+    return nullptr;
 }
 
 static CachedImage* getCachedImage(Element* element)