Setting a custom background on a HiDPI display will result in the background only being applied to …

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 851c34a8cc99e43864b5b7c571373502e2d14976..b6a29f8d12fe118de16d21368b0ca616f585d612 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -770,6 +770,7 @@ void RenderWidget::PaintRect(const gfx::Rect& rect,
     // Canvas could contain multiple update rects. Clip to given rect so that
     // we don't accidentally clear other update rects.
     canvas->save();
+    canvas->scale(device_scale_factor_, device_scale_factor_);
     canvas->clipRect(gfx::RectToSkRect(rect));
     canvas->drawPaint(paint);
     canvas->restore();