[gtk] (31 commits) Non-fast-forward update to branch wip/chergert/dropdown-show-arrow

[Christian Hergert <chergert src gnome org>]

The branch 'wip/chergert/dropdown-show-arrow' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  0edcc6d... dropdown: add GtkDropDown:show-arrow property

Commits added to the branch:

  d939f37... win32: Comment out unused function (*)
  6ec6bca... win32: Remove unused variables (*)
  75370a2... pathbar: Use correct marshaler (*)
  38461ee... gdk: Make GDK_DEBUG GL backend selection global (*)
  9012a03... widget-factory: Name the images pages (*)
  04da2ff... surface: Use g_clear_thing() (*)
  3f5107c... inspector: Export gtk_inspector_init (*)
  9e88275... Merge branch 'matthiasc/for-master' into 'master' (*)
  ae8de71... build: Add a HAVE_EGL define to config.h (*)
  bfb158d... egl: Move initialization code and port Wayland (*)
  70607f5... x11: Port to shared EGL code (*)
  032eb15... glcontext: The content cannot be the current context (*)
  c8204a9... surface: Add a private struct (*)
  aba37c4... display: Get carried away by extension checker (*)
  d128ffc... egl: Move EGLSurface handling to GdkSurface (*)
  f8b9b30... egl: Move extension checks to GdkDisplay (*)
  482845b... wayland: Remove initial GL API bind (*)
  111c276... cairo-gl: Don't leak framebuffers (*)
  64f10ef... gdk: Remove unused gdk_gl_texture_quads() function (*)
  03cc603... glcontext: Remove unused functionality (*)
  2ff1ea5... egl: Unify contexts (*)
  3ca84c4... glcontext: Handle failure of eglBindAPI() (*)
  bc7c0d0... egl: Support EGL_KHR_no_config_context (*)
  7ede468... gdk: Add a request_hdr argument to begin_frame() (*)
  5eb42dd... gdk: Add GDK_DEBUG=hdr (*)
  cdc8523... egl: Implement HDR support (*)
  0969d9d... Merge branch 'wip/otte/gl-hdr' into 'master' (*)
  f819e88... gdk: Fix an oversight (*)
  4360bc3... Merge branch 'matthiasc/for-master' into 'master' (*)
  cd45e6e... dropdown: add GtkDropDown:show-arrow property
  cd2debd... dropdown: fix extraneous * in documentation

(*) This commit already existed in another branch; no separate mail sent