Merge "StagefrightMetadataRetriever: handle mSource being NULL" into nyc-dev
am: c280a25

* commit 'c280a25f5a7d36bc2f395c2e6c294d62785ca276':
  StagefrightMetadataRetriever: handle mSource being NULL

Change-Id: I38e01d01da43daf89bef7f09f607c6e4582bfe8b