cc: Fix nullptr dereference when capturing skps.

cc/playback/display_list_raster_source.cc

Index: cc/playback/display_list_raster_source.cc
diff --git a/cc/playback/display_list_raster_source.cc b/cc/playback/display_list_raster_source.cc
index 3f740af4a722dd9a3ad9f2f0cb79fc5c03d0087f..38bc5e86138b6228e37195f554e9a4d9966c435c 100644
--- a/cc/playback/display_list_raster_source.cc
+++ b/cc/playback/display_list_raster_source.cc
@@ -387,8 +387,11 @@ skia::RefPtr<SkPicture> DisplayListRasterSource::GetFlattenedPicture() {
   SkPictureRecorder recorder;
   SkCanvas* canvas = recorder.beginRecording(display_list_rect.width(),
                                              display_list_rect.height());
-  if (!display_list_rect.IsEmpty())
-    PlaybackToCanvas(canvas, display_list_rect, display_list_rect, 1.0);
+  if (!display_list_rect.IsEmpty()) {
+    PrepareForPlaybackToCanvas(canvas, display_list_rect, display_list_rect,
+                               1.f);
+    RasterCommon(canvas, nullptr, display_list_rect, display_list_rect, 1.f);
+  }
   skia::RefPtr<SkPicture> picture =
       skia::AdoptRef(recorder.endRecordingAsPicture());