YUVImage is a container class to hold YUV data and provide various utilities, e.g. to set/get pixel values for different YUV formats, fast copying routines, etc. Currently supported YUV420 Planar and YUV420 Semi Planar. YUVCanvas holds a reference to a YUVImage on which it can do various drawing operations. Change-Id: I052a57b7fbc834efe1626914f76c04c091996cac