Bug 969761: use device pixels when chosing camera preview size
Merge pull request #16152 from davidflanagan/bug969761

Bug 969761: use device pixels when chosing camera preview size r=justindarc
Revert "Merge pull request #16127 from changm/bug968478"

This reverts commit 88bda206b1def5d4beac3be851c904414563bea3.
Revert "Merge pull request #16126 from changm/bug968311"

This reverts commit 32b7cf41d72e8d636fa84e768f2821407316b299.