Deal gracefully with null {GraphicsContext,SkPictureBuilder}.endRecording() results.

third_party/WebKit/Source/core/paint/SVGShapePainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/SVGShapePainter.h"
 
 #include "core/layout/svg/LayoutSVGResourceMarker.h"
 #include "core/layout/svg/LayoutSVGShape.h"
 #include "core/layout/svg/SVGLayoutSupport.h"
 #include "core/layout/svg/SVGMarkerData.h"
@@ skipping 186 matching lines @@
         if (LayoutSVGResourceMarker* marker = SVGMarkerData::markerForType((*markerPositions)[i].type, markerStart, markerMid, markerEnd)) {
             SkPictureBuilder pictureBuilder(boundingBox, nullptr, &paintInfo.context);
             PaintInfo markerPaintInfo(pictureBuilder.context(), paintInfo);
 
             // It's expensive to track the transformed paint cull rect for each
             // marker so just disable culling. The shape paint call will already
             // be culled if it is outside the paint info cull rect.
             markerPaintInfo.m_cullRect.m_rect = LayoutRect::infiniteIntRect();
 
             paintMarker(markerPaintInfo, *marker, (*markerPositions)[i], strokeWidth);
-            pictureBuilder.endRecording()->playback(paintInfo.context.canvas());
+            RefPtr<const SkPicture> recording = pictureBuilder.endRecording();
+            if (recording)
+                recording->playback(paintInfo.context.canvas());
         }
     }
 }
 
 void SVGShapePainter::paintMarker(const PaintInfo& paintInfo, LayoutSVGResourceMarker& marker, const MarkerPosition& position, float strokeWidth)
 {
     // An empty viewBox disables rendering.
     SVGMarkerElement* markerElement = toSVGMarkerElement(marker.element());
     ASSERT(markerElement);
     if (markerElement->hasAttribute(SVGNames::viewBoxAttr) && markerElement->viewBox()->currentValue()->isValid() && markerElement->viewBox()->currentValue()->value().isEmpty())
         return;
 
     TransformRecorder transformRecorder(paintInfo.context, marker, marker.markerTransformation(position.origin, position.angle, strokeWidth));
     Optional<FloatClipRecorder> clipRecorder;
     if (SVGLayoutSupport::isOverflowHidden(&marker))
         clipRecorder.emplace(paintInfo.context, marker, paintInfo.phase, marker.viewport());
     SVGContainerPainter(marker).paint(paintInfo);
 }
 
 } // namespace blink