Refactor bits of libgtkui

* Switch to using CHROMEG_CALLBACK in GtkUi.
* Remove code that's conditional on GTK version < 3.10.  The earlist supported
  version is now 3.10.8.
* Ensure correct ordering of NativeThemeGtk::OnThemeChanged and
  GtkUi::OnThemeChanged.  The ordering was correct before, but was dependent on
  glib dispatching events in the right order.  Changed GtkUi::OnThemeChanged()
  to call NativeThemeGtk::OnThemeChanged().


Change-Id: I19a4fbab8e4ad44445945e31fcd740faea91f5de
Commit-Queue: Thomas Anderson <>
Reviewed-by: Peter Kasting <>
Auto-Submit: Thomas Anderson <>
Cr-Commit-Position: refs/heads/master@{#663375}
5 files changed