[LayoutNG] Remove duplicated DrawingRecroder in NGBoxFragmentPainter

NGBoxFragmentPainter::PaintBlockFlowContents creates
DrawingRecorer before calling PaintMask, but PaintMask creates
another DrawingRecorder.

This patch removes the duplicated instantiation.

The structure, to create DrawingRecorder inside of
PaintMask, matches to BoxPainter.

blink_perf.paint_layout_ng does't show much differences:
https://pinpoint-dot-chromeperf.appspot.com/job/15d7ebcb340000

Change-Id: I68919799eb00083cb4e782c41ff7dfa6bbadd9b2
Bug: 936024
Reviewed-on: https://chromium-review.googlesource.com/c/1488490Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635704}

third_party/blink/renderer/core/paint/ng/ng_box_fragment_painter.cc

@@ -328,11 +328,6 @@ void NGBoxFragmentPainter::PaintBlockFlowContents(
     return;
 
   if (paint_info.phase == PaintPhase::kMask) {
-    if (DrawingRecorder::UseCachedDrawingIfPossible(
-            paint_info.context, box_fragment_, paint_info.phase))
-      return;
-    DrawingRecorder recorder(paint_info.context, box_fragment_,
-                             paint_info.phase);
     PaintMask(paint_info, paint_offset);
     return;
   }