Enable immersive fullscreen on Windows Ash.

ash/shelf/shelf_layout_manager.cc

Index: ash/shelf/shelf_layout_manager.cc
diff --git a/ash/shelf/shelf_layout_manager.cc b/ash/shelf/shelf_layout_manager.cc
index f13ea079023459d5b94dccd053abe87324ffcd63..9c5acabaacb4bfef7124735f9d188dba22ccf511 100644
--- a/ash/shelf/shelf_layout_manager.cc
+++ b/ash/shelf/shelf_layout_manager.cc
@@ -393,19 +393,11 @@ void ShelfLayoutManager::RemoveObserver(ShelfLayoutManagerObserver* observer) {
 // ShelfLayoutManager, Gesture functions:
 
 void ShelfLayoutManager::OnGestureEdgeSwipe(const ui::GestureEvent& gesture) {
-  // Edge swipe should exit fullscreen, show the tray, and disable auto-hide.
-
-  if (workspace_controller_->GetWindowState() ==
-      WORKSPACE_WINDOW_STATE_FULL_SCREEN) {

[pkotwicz, 2014/03/13 18:08:45]

Do we still want this behavior when
ash::wm::WindowState::hide_shelf_when_fullscreen() is true for the topmost
window?
This is the case if the topmost window is in HTML5 fullscreen. e.g
http://html5-demos.appspot.com/static/fullscreen.html

[zturner, 2014/03/13 19:28:09]

Good point, I'll make this fix.

-    accelerators::ToggleFullscreen();
-  }
-
-  ShelfVisibilityState visibility = CalculateShelfVisibility();
-  if (visibility == SHELF_AUTO_HIDE &&
-      CalculateAutoHideState(visibility) == SHELF_AUTO_HIDE_HIDDEN) {
-    SetState(SHELF_VISIBLE);
-    SetAutoHideBehavior(SHELF_AUTO_HIDE_BEHAVIOR_NEVER);
-  }
+  // Edge swipe should display the shelf.
+  gesture_drag_auto_hide_state_ = SHELF_AUTO_HIDE_SHOWN;
+  gesture_drag_status_ = GESTURE_DRAG_COMPLETE_IN_PROGRESS;

[pkotwicz, 2014/03/13 18:08:45]

Shouldn't we be calling SetAutoHideBehavior() or UpdateVisibilityState() as
appropriate similar to ShelfLayoutManager::CompleteGestureDrag()

Otherwise, we might revert back to SHELF_VISIBLE the next time that
UpdateVisibilityState() is called?

[zturner, 2014/03/13 19:28:09]

Unfortunately this class and the logic is a little confusing.  We basically want
to mimic the behavior of doing a drag gesture, but a drag gesture comes in
multiple parts and a win8 edge swipe is just a single notification.  So the
logic of beginning a drag, updating a drag, and completing a drag is merged
here.

If all we do is call SetAutoHideBehavior() or UpdateVisibilityState(), the value
we would want to set it to is the same as the value it already is.  i.e. we
don't actually want to change the auto-hide behavior.  All we want to do is make
the currently auto-hidden shelf reveal itself temporarily.

[pkotwicz, 2014/03/13 19:52:48]

Is it possible for a user to do an edge swipe while the shelf has
ShelfVisibilityState SHELF_VISIBLE

+  SetState(SHELF_AUTO_HIDE);
+  gesture_drag_status_ = GESTURE_DRAG_NONE;
 }
 
 void ShelfLayoutManager::StartGestureDrag(const ui::GestureEvent& gesture) {