Scrollbar ThumbLength is not updated when window size is changed.

cc/layers/painted_scrollbar_layer.cc

Index: cc/layers/painted_scrollbar_layer.cc
diff --git a/cc/layers/painted_scrollbar_layer.cc b/cc/layers/painted_scrollbar_layer.cc
index c0b2a728e3c9077c46a7f194dce94174d0780fd0..161a892c5a12f90e7c5d882b4275ba0f355af925 100644
--- a/cc/layers/painted_scrollbar_layer.cc
+++ b/cc/layers/painted_scrollbar_layer.cc
@@ -189,10 +189,8 @@ void PaintedScrollbarLayer::UpdateThumbAndTrackGeometry() {
   UpdateProperty(scrollbar_->Location(), &location_);
   UpdateProperty(scrollbar_->IsOverlay(), &is_overlay_);
   UpdateProperty(scrollbar_->HasThumb(), &has_thumb_);
-  if (has_thumb_) {
-    UpdateProperty(scrollbar_->ThumbThickness(), &thumb_thickness_);
-    UpdateProperty(scrollbar_->ThumbLength(), &thumb_length_);
-  }
+  UpdateProperty(scrollbar_->ThumbThickness(), &thumb_thickness_);
+  UpdateProperty(scrollbar_->ThumbLength(), &thumb_length_);
 }
 
 bool PaintedScrollbarLayer::Update(ResourceUpdateQueue* queue,