Make tile size a function of the device scale factor.

cc/layers/picture_layer_impl.h

Index: cc/layers/picture_layer_impl.h
diff --git a/cc/layers/picture_layer_impl.h b/cc/layers/picture_layer_impl.h
index f6a65242bf87195c61f8e5eac4ebc00f4b337abd..1fa3b725c42546036c26d38cf339a764b2784c71 100644
--- a/cc/layers/picture_layer_impl.h
+++ b/cc/layers/picture_layer_impl.h
@@ -29,6 +29,9 @@ class CC_EXPORT PictureLayerImpl
     : public LayerImpl,
       NON_EXPORTED_BASE(public PictureLayerTilingClient) {
  public:
+  // TODO(crbug.com/622885): This should scale with the device scale factor.
+  enum : int { kMaxUntiledContentSize = 512 };
+
   static std::unique_ptr<PictureLayerImpl> Create(LayerTreeImpl* tree_impl,
                                                   int id,
                                                   bool is_mask) {