Refactoring ImageBuffer to decouple it from Canvas2DLayerBridge

Source/core/frame/Frame.cpp

Index: Source/core/frame/Frame.cpp
diff --git a/Source/core/frame/Frame.cpp b/Source/core/frame/Frame.cpp
index 3109cb225fd777456bebb6368d9ca6efa6162734..98c1b17808d24fe1e80124feacb6f1836bdc6c1d 100644
--- a/Source/core/frame/Frame.cpp
+++ b/Source/core/frame/Frame.cpp
@@ -649,9 +649,10 @@ PassOwnPtr<DragImage> Frame::nodeImage(Node* node)
     paintingRect.setWidth(paintingRect.width() * deviceScaleFactor);
     paintingRect.setHeight(paintingRect.height() * deviceScaleFactor);
 
-    OwnPtr<ImageBuffer> buffer(ImageBuffer::create(paintingRect.size(), deviceScaleFactor));
+    OwnPtr<ImageBuffer> buffer = ImageBuffer::create(paintingRect.size());
     if (!buffer)
         return nullptr;
+    buffer->context()->scale(FloatSize(deviceScaleFactor, deviceScaleFactor));
     buffer->context()->translate(-paintingRect.x(), -paintingRect.y());
     buffer->context()->clip(FloatRect(0, 0, paintingRect.maxX(), paintingRect.maxY()));
 
@@ -678,9 +679,10 @@ PassOwnPtr<DragImage> Frame::dragImageForSelection()
     paintingRect.setWidth(paintingRect.width() * deviceScaleFactor);
     paintingRect.setHeight(paintingRect.height() * deviceScaleFactor);
 
-    OwnPtr<ImageBuffer> buffer(ImageBuffer::create(paintingRect.size(), deviceScaleFactor));
+    OwnPtr<ImageBuffer> buffer = ImageBuffer::create(paintingRect.size());
     if (!buffer)
         return nullptr;
+    buffer->context()->scale(FloatSize(deviceScaleFactor, deviceScaleFactor));
     buffer->context()->translate(-paintingRect.x(), -paintingRect.y());
     buffer->context()->clip(FloatRect(0, 0, paintingRect.maxX(), paintingRect.maxY()));