Remove PaintInfo's paintingRoot

third_party/WebKit/Source/core/frame/LocalFrame.cpp

Index: third_party/WebKit/Source/core/frame/LocalFrame.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalFrame.cpp b/third_party/WebKit/Source/core/frame/LocalFrame.cpp
index eca2f188fe6f8acee6e9ae4fb8fdd189606af2ad..bf27b50bd42a5a2cd20ae876e79b466a6f8a744a 100644
--- a/third_party/WebKit/Source/core/frame/LocalFrame.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalFrame.cpp
@@ -60,6 +60,8 @@
 #include "core/page/FocusController.h"
 #include "core/page/Page.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
+#include "core/paint/ObjectPainter.h"
+#include "core/paint/PaintInfo.h"
 #include "core/paint/PaintLayer.h"
 #include "core/paint/TransformRecorder.h"
 #include "core/svg/SVGDocumentExtensions.h"
@@ -101,7 +103,6 @@ public:
     {
         if (node && node->layoutObject())
             node->layoutObject()->updateDragState(false);
-        frame->view()->setNodeToDraw(0);
     }
 
     RawPtrWillBeMember<LocalFrame> frame;
@@ -653,18 +654,41 @@ PassOwnPtr<DragImage> LocalFrame::nodeImage(Node& node)
     const ScopedFramePaintingState state(this, &node);
 
     m_view->updateAllLifecyclePhases();
-
-    m_view->setNodeToDraw(&node); // Enable special sub-tree drawing mode.
-
-    // Document::updateLayout may have blown away the original LayoutObject.
     LayoutObject* layoutObject = node.layoutObject();
     if (!layoutObject)
         return nullptr;
 
-    IntRect rect;
+    // Directly paint boxes as if they are a stacking context.
+    if (layoutObject->isBox() && layoutObject->container()) {
+        IntRect boundingBox = layoutObject->absoluteBoundingBoxRectIncludingDescendants();
+        LayoutPoint paintOffset = boundingBox.location();
+        paintOffset -= layoutObject->offsetFromContainer(layoutObject->container(), LayoutPoint());
+
+        float deviceScaleFactor = m_host->deviceScaleFactor();
+        boundingBox.scale(deviceScaleFactor);
+        SkPictureBuilder pictureBuilder(SkRect::MakeIWH(boundingBox.width(), boundingBox.height()));
+        {
+            PaintInfo paintInfo(pictureBuilder.context(), boundingBox, PaintPhase::PaintPhaseForeground, GlobalPaintFlattenCompositingLayers, 0);
+
+            AffineTransform transform;
+            transform.scale(deviceScaleFactor, deviceScaleFactor);
+            transform.translate(-boundingBox.x(), -boundingBox.y());
+            TransformRecorder transformRecorder(pictureBuilder.context(), *this, transform);

[chrishtr, 2016/01/19 18:29:21]

The code here looks like it duplicates paintIntoDragImage. Refactor into a
helper.

[pdr., 2016/01/19 23:29:21]

Good idea. This required some invasive refactoring because there are two ways
the context is used. I think the code ended up in a nicer place.

+
+            ObjectPainter(*layoutObject).paintAsPseudoStackingContext(paintInfo, LayoutPoint(paintOffset));
+        }
+        RefPtr<const SkPicture> recording = pictureBuilder.endRecording();
+        RefPtr<SkImage> skImage = adoptRef(SkImage::NewFromPicture(recording.get(),
+            SkISize::Make(boundingBox.width(), boundingBox.height()), nullptr, nullptr));
+        RefPtr<Image> image = StaticBitmapImage::create(skImage.release());
+        return DragImage::create(image.get(), LayoutObject::shouldRespectImageOrientation(layoutObject), deviceScaleFactor, InterpolationHigh);
+    }
 
+    // FIXME(pdr): This will also paint the background if the object contains transparency. We can
+    // directly call layoutObject->paint(...) (see: ObjectPainter::paintAsPseudoStackingContext) but
+    // painters are inconsistent about which transform space they expect (see: svg, inlines, etc.)
     return paintIntoDragImage(*layoutObject, LayoutObject::shouldRespectImageOrientation(layoutObject),
-        GlobalPaintFlattenCompositingLayers, layoutObject->paintingRootRect(rect));
+        GlobalPaintFlattenCompositingLayers, layoutObject->absoluteBoundingBoxRectIncludingDescendants());
 }
 
 PassOwnPtr<DragImage> LocalFrame::dragImageForSelection(float opacity)