[gtk] (19 commits) ...Merge branch 'ebassi/for-master' into 'master'

[Emmanuele Bassi <ebassi src gnome org>]

Summary of changes:

  0d6e4f7... demo: Add more accessibility labels to the UI (*)
  429c7fc... a11y: Add role exception for GtkScrolledWindow (*)
  e940704... a11y: Ignore more structural roles when computing labels (*)
  bfb054a... a11y: Icons in WindowControls are presentational only (*)
  a59889a... Unrealize the ATContext in StackPage on dispose (*)
  d34936c... Handle empty stack pages when creating an ATContext (*)
  995daa1... a11y: GtkStack is a group of stack pages (*)
  e49e084... a11y: Use the stack page title as its accessible label (*)
  87f92a9... a11y: Add more accessibility labels to GtkNotebook (*)
  f8bb206... a11y: Icons in buttons are presentational (*)
  d4ddfdc... a11y: Set the role on GtkSearchBar (*)
  ebda736... a11y: Mark SearchEntry icons as presentational (*)
  61e980b... a11y: Add accessible actions to GtkSearchEntry (*)
  75f9b83... Establish a control relation between demo search and list (*)
  0d7fcdd... a11y: Add more accessible data to GtkTreeExpander (*)
  b9ad317... a11y: Document GtkRevealer's accessible state (*)
  abc9b40... a11y: Implement atspi.Text.ScrollSubstringTo for GtkTextVie (*)
  8203d9c... a11y: Use GROUP role for ShortcutsShortcut (*)
  92ca3a3... Merge branch 'ebassi/for-master' into 'master'

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