Comment 3 for bug 1420678

Found the source of the regression:

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revno: 2183 [merge]
author: Daniel van Vugt <email address hidden>
committer: Tarmac
branch nick: development-branch
timestamp: Fri 2014-12-19 21:52:32 +0000
message:
  Split post_update() into separate gl_swap_buffers() and flip().

  On some platforms this provides a significant performance boost, as
  GL resources and client buffers can be released after the gl_swap_buffers
  without having to wait for the flip.

  This solves most of LP: #1264934, and unblocks work on LP: #1350716 and
  possibly unblocks LP: #1350725 too. Fixes: https://bugs.launchpad.net/bugs/1264934, https://bugs.launchpad.net/bugs/1350716.

  Approved by Alberto Aguirre, Cemil Azizoglu, Alan Griffiths, PS Jenkins bot, Robert Carr.
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