Merge pull request #8516 from dominickuo/email-support-save-music

Bug 838009 - Enable saving/playing music in email attachment, r=asutherland, a=leo+
Merge pull request #8569 from dominickuo/video-support-open-activity

Bug 838655 - [video] support open activity to play videos from blobs, r=timdream, a=leo+
Bug 838006 - Modify gallery and email to support attaching image files from picker