found by cppcheck
[libfreerdp/codec/include/bitmap.c:112] -> [libfreerdp/codec/include/bitmap.c:95]: (warning) Either the condition '!pbSrcBuffer' is redundant or there is pointer arithmetic with NULL pointer.
[libfreerdp/codec/include/bitmap.c:112] -> [libfreerdp/codec/include/bitmap.c:96]: (warning) Either the condition '!pbDestBuffer' is redundant or there is pointer arithmetic with NULL pointer.
[client/X11/xf_floatbar.c:800] -> [client/X11/xf_floatbar.c:796]: (warning) Either the condition '!floatbar' is redundant or there is possible null pointer dereference: floatbar.
[client/X11/xf_floatbar.c:800] -> [client/X11/xf_floatbar.c:797]: (warning) Either the condition '!floatbar' is redundant or there is possible null pointer dereference: floatbar.
[client/X11/xf_floatbar.c:800] -> [client/X11/xf_floatbar.c:798]: (warning) Either the condition '!floatbar' is redundant or there is possible null pointer dereference: floatbar.
[libfreerdp/codec/dsp.c:1156] -> [libfreerdp/codec/dsp.c:1154]: (warning) Either the condition '!srcFormat' is redundant or there is possible null pointer dereference: srcFormat.
[channels/drdynvc/client/drdynvc_main.c:1453] -> [channels/drdynvc/client/drdynvc_main.c:1450]: (warning) Either the condition '!drdynvc' is redundant or there is possible null pointer dereference: drdynvc.
[channels/audin/client/opensles/audin_opensl_es.c:98] -> [channels/audin/client/opensles/audin_opensl_es.c:94]: (warning) Either the condition '!opensles' is redundant or there is possible null pointer dereference: opensles.
[channels/audin/client/opensles/audin_opensl_es.c:159] -> [channels/audin/client/opensles/audin_opensl_es.c:153]: (warning) Either the condition '!opensles' is redundant or there is possible null pointer dereference: opensles.
The spec doesn't require that FRAME_BEGIN, REGION, TILESET, and FRAME_END come all in one
chunk. This patch adds the necessary state saving.
A unitary test is also added.