SetNeedsRedraw directly when updating a visible tile.

cc/layers/picture_layer.cc

Index: cc/layers/picture_layer.cc
diff --git a/cc/layers/picture_layer.cc b/cc/layers/picture_layer.cc
index c56ff8be082b67dbf33e8db8193481efc99b2307..795908b501d566349c0b62de9e3defd1cf6a0b2d 100644
--- a/cc/layers/picture_layer.cc
+++ b/cc/layers/picture_layer.cc
@@ -57,7 +57,7 @@ void PictureLayer::PushPropertiesTo(LayerImpl* base_layer) {
   // See PictureLayerImpl::PushPropertiesTo for more details.
   layer_impl->invalidation_.Clear();
   layer_impl->invalidation_.Swap(&pile_invalidation_);
-  layer_impl->UpdatePile(PicturePileImpl::CreateFromOther(&pile_));
+  layer_impl->UpdatePile(CreatePicturePileImpl());
 }
 
 void PictureLayer::SetLayerTreeHost(LayerTreeHost* host) {
@@ -165,6 +165,10 @@ void PictureLayer::UpdateCanUseLCDText() {
     client_->DidChangeLayerCanUseLCDText();
 }
 
+scoped_refptr<PicturePileImpl> PictureLayer::CreatePicturePileImpl() {
+  return PicturePileImpl::CreateFromOther(&pile_);
+}
+
 skia::RefPtr<SkPicture> PictureLayer::GetPicture() const {
   // We could either flatten the PicturePile into a single SkPicture,
   // or paint a fresh one depending on what we intend to do with the