Have Document::markers() return a reference

Source/core/frame/FrameView.cpp

Index: Source/core/frame/FrameView.cpp
diff --git a/Source/core/frame/FrameView.cpp b/Source/core/frame/FrameView.cpp
index 406e38f0fbe3b8659b263fe7f3ed748bb9483600..edf302b5675a38529d99746eaf75d1e2ecd6e646 100644
--- a/Source/core/frame/FrameView.cpp
+++ b/Source/core/frame/FrameView.cpp
@@ -2301,7 +2301,7 @@ void FrameView::invalidateScrollbarRect(Scrollbar* scrollbar, const IntRect& rec
 
 void FrameView::getTickmarks(Vector<IntRect>& tickmarks) const
 {
-    tickmarks = frame().document()->markers()->renderedRectsForMarkers(DocumentMarker::TextMatch);
+    tickmarks = frame().document()->markers().renderedRectsForMarkers(DocumentMarker::TextMatch);
 }
 
 IntRect FrameView::windowResizerRect() const
@@ -2668,7 +2668,7 @@ void FrameView::paintContents(GraphicsContext* p, const IntRect& rect)
     }
 
     if (m_paintBehavior == PaintBehaviorNormal)
-        document->markers()->invalidateRenderedRectsForMarkersInRect(rect);
+        document->markers().invalidateRenderedRectsForMarkersInRect(rect);
 
     if (document->printing())
         m_paintBehavior |= PaintBehaviorFlattenCompositingLayers;