Merge pull request #7686 from Rik/banding-jones-829075

Bug 829075 - Lock screen background show significant banding r=timdream a=tracking-b2g18+(cherry picked from commit 2dac54c4032cbd00698eb6f6a6c6408cfd16a8fb)
Bug 836293 - Lockscreen wallpaper is not updated after changing homescreen wallpaper r=timdream
(cherry picked from commit 7f655a193dcbcb475762d27db54f6cc8bab0ba74)
Merge pull request #7949 from Rik/lockscreen-camera-836300

Bug 836300 - Camera activity doesn't return an image at the requested si...(cherry picked from commit f7223357e31cbb66206a3e70dee8611d3bba0548)