am 021b7b44: Add a static method to obtain the mime type from extension.

Merge commit '021b7b443fa4bb24ec73d0c09cf019c14eba67bc' into eclair-mr2-plus-aosp

* commit '021b7b443fa4bb24ec73d0c09cf019c14eba67bc':
  Add a static method to obtain the mime type from extension.