Merged requested to merge verdre/gnome-shell:fix-blur-crash into master
When we're painting off-stage, for example because we're screencasting or taking a screenshot, there won't be a stage-view associated with the paint context. The BlurEffect previously didn't handle that case and would crash.
Fix that and handle that case by assuming the scale is 1 and not offsetting the rectangle we blit from the draw framebuffer.
Fixes #3301 (closed)