Enable shelf gestures in immersive mode

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 4cb6af1681a3eb122607b6b9608edf5e478a3baa..37875a931abe2de8e021154664d7ea57771eeaef 100644
--- a/ash/shelf/shelf_layout_manager.cc
+++ b/ash/shelf/shelf_layout_manager.cc
@@ -447,6 +447,11 @@ void ShelfLayoutManager::CompleteGestureDrag(const ui::GestureEvent& gesture) {
       auto_hide_behavior_ != SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS) {
     gesture_drag_status_ = GESTURE_DRAG_NONE;
     SetAutoHideBehavior(SHELF_AUTO_HIDE_BEHAVIOR_ALWAYS);
+    aura::Window* active = wm::GetActiveWindow();

[Harry McCleave, 2013/05/02 20:36:32]

Would this not be better served as an if/else pairing (the current flow of
SetAuto...(ALWAYS); SetAutoHide...(NEVER) in the
active/fullscreen/MinimalChromeKey case seems cumbersome.

[rharrison, 2013/05/16 17:31:04]

Done.

+    if (active &&
+        wm::IsWindowFullscreen(active) &&
+        active->GetProperty(kFullscreenUsesMinimalChromeKey))

[sadrul, 2013/05/02 20:43:58]

I am not familiar with this magical key. But it would be good to
SetAutoHideBehavior just once, instead of setting it to ALWAYS (449), and
setting it back to NEVER (454).

[rharrison, 2013/05/16 17:31:04]

Done.

+      SetAutoHideBehavior(SHELF_AUTO_HIDE_BEHAVIOR_NEVER);

[pkotwicz, 2013/05/06 20:50:37]

Drive by:
- You should probably use RootWindowController::GetFullscreenWindow() For
instance, in immersive fullscreen, the bookmark bubble could be active, but we
are theoretically still fullscreen.

[rharrison, 2013/05/16 17:31:04]

Done.

   } else if (gesture_drag_auto_hide_state_ == SHELF_AUTO_HIDE_SHOWN &&
              auto_hide_behavior_ != SHELF_AUTO_HIDE_BEHAVIOR_NEVER) {
     gesture_drag_status_ = GESTURE_DRAG_NONE;