Merge remote-tracking branch 'remotes/kraxel/tags/vnc-20180112-pull-request' into...

Merge remote-tracking branch 'remotes/kraxel/tags/vnc-20180112-pull-request' into staging

vnc: limit memory usage (CVE-2017-15124)

# gpg: Signature made Fri 12 Jan 2018 12:57:22 GMT
# gpg:                using RSA key 0x4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/vnc-20180112-pull-request:
  ui: mix misleading comments & return types of VNC I/O helper methods
  ui: add trace events related to VNC client throttling
  ui: place a hard cap on VNC server output buffer size
  ui: fix VNC client throttling when forced update is requested
  ui: fix VNC client throttling when audio capture is active
  ui: refactor code for determining if an update should be sent to the client
  ui: correctly reset framebuffer update state after processing dirty regions
  ui: introduce enum to track VNC client framebuffer update request state
  ui: track how much decoded data we consumed when doing SASL encoding
  ui: avoid pointless VNC updates if framebuffer isn't dirty
  ui: remove redundant indentation in vnc_client_update
  ui: remove unreachable code in vnc_update_client
  ui: remove 'sync' parameter from vnc_update_client
  vnc: fix debug spelling

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>