Wallpaper resize extents compositor lock timeout.

ash/rotator/screen_rotation_animator.cc

Index: ash/rotator/screen_rotation_animator.cc
diff --git a/ash/rotator/screen_rotation_animator.cc b/ash/rotator/screen_rotation_animator.cc
index 31a54537dd859ca1f3d8535baabb1442e81af0d6..0198d8ab02ae676e6f98ffc318f0f986b1b9eaa4 100644
--- a/ash/rotator/screen_rotation_animator.cc
+++ b/ash/rotator/screen_rotation_animator.cc
@@ -225,8 +225,14 @@ void ScreenRotationAnimator::SetRotation(
     display::Display::Rotation old_rotation,
     display::Display::Rotation new_rotation,
     display::Display::RotationSource source) {
+  // Allow compositor locks to extend timeout, so that screen rotation only
+  // takes output copy after contents are properlly resized, such as wallpaper
+  // and ARC apps.
+  ui::Compositor* compositor = root_window_->layer()->GetCompositor();
+  compositor->set_allow_locks_to_extend_timeout(true);
   Shell::Get()->display_manager()->SetDisplayRotation(display_id_, new_rotation,
                                                       source);
+  compositor->set_allow_locks_to_extend_timeout(false);
   const display::Display display =
       Shell::Get()->display_manager()->GetDisplayForId(display_id_);
   old_layer_tree_owner_->root()->SetTransform(