Merge commit '3d7b8d1aa6a362292f56defbe8fb2d5653f79282' * commit '3d7b8d1aa6a362292f56defbe8fb2d5653f79282': Use a ref-counted callback interface for Camera.
Merge commit '3d7b8d1aa6a362292f56defbe8fb2d5653f79282' * commit '3d7b8d1aa6a362292f56defbe8fb2d5653f79282': Use a ref-counted callback interface for Camera.