Update from https://crrev.com/312398

cc/resources/tiling_set_raster_queue_required.cc

Index: cc/resources/tiling_set_raster_queue_required.cc
diff --git a/cc/resources/tiling_set_raster_queue_required.cc b/cc/resources/tiling_set_raster_queue_required.cc
index 7d76d2c1367fbcb44b89f1c05101252ac01b3860..89ddb044255ed905ddcb963dffd62276e324305b 100644
--- a/cc/resources/tiling_set_raster_queue_required.cc
+++ b/cc/resources/tiling_set_raster_queue_required.cc
@@ -25,7 +25,12 @@ TilingSetRasterQueueRequired::TilingSetRasterQueueRequired(
   // resolution is not HIGH_RESOLUTION.
   PictureLayerTiling* tiling =
       tiling_set->FindTilingWithResolution(HIGH_RESOLUTION);
-  DCHECK(tiling);
+  // If we don't have a high res tiling, then this queue will yield no tiles.
+  // See PictureLayerImpl::CanHaveTilings for examples of when a HIGH_RESOLUTION
+  // tiling would not be generated.
+  if (!tiling)
+    return;
+
   iterator_ = TilingIterator(tiling, &tiling->tiling_data_);
   while (!iterator_.done() && !IsTileRequired(*iterator_))
     ++iterator_;