Media Galleries API Metadata: SafeMediaMetadataParser and IPCTunnelDataReader.

BUG=318450

Review URL: https://codereview.chromium.org/103283003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244310 0039d316-1c4b-4281-b951-d872f2087c98
Replace OutputSnapshot |is_internal| with check against 'type == OUTPUT_TYPE_INTERNAL'

BUG=None

Review URL: https://codereview.chromium.org/132983002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244311 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244311