Adds a control function that allows the caller to get
the size of the current frame.

Change-Id: Iddfdedc0f3aa9aa46119f87d294681c82f275c9f

When it's configured, make sure it can be configured. When it's not,
make sure it fails.

Change-Id: I857d4b8014547ddbad70395f17e58d5838bd142f

size_t -> uint32 in the call to vpx_codec_decode()

Change-Id: Ibf39d3749321c97292b35ac0631fa22211cff800

'ref_frame_map' is initialized to -1. avoids using an invalid index  if
VP9_GET_REFERENCE/VP8_COPY_REFERENCE controls are issued after a decode
error.

Change-Id: I4599762c4d0b07a5943a72bf4a86ccb596cc062a

if the decode of the first frame fails, frame_to_show may not be set.
fixes a crash in vpxdec with corrupt data.

Change-Id: I5ab9476d005778a13fd42a39d05876bb6c90a93c

When a valid data pointer is given make sure the size is greater than
zero.
A previous check for vp9 was incorrectly removed in:
70500747 Make the api behavior conform to api spec.

No semantics for valid pointers + 0-sized frames are defined for VPx
codecs, so move the check to vpx_codec_decode(). This avoids an assert
in vp9.

+ add some basic invalid param testing for decoder init/decode/destroy

Change-Id: I99f9cef6076d15874fd72ac973f2685d8a2353c3