ash/immersive mode: Hide the launcher when entering immersive mode

ash/wm/workspace/workspace_manager.cc

Index: ash/wm/workspace/workspace_manager.cc
diff --git a/ash/wm/workspace/workspace_manager.cc b/ash/wm/workspace/workspace_manager.cc
index 0426d781a3da2da6555edca6d1a35432201e3953..95c63f12e869ae75fee2424952b6417e72cc524c 100644
--- a/ash/wm/workspace/workspace_manager.cc
+++ b/ash/wm/workspace/workspace_manager.cc
@@ -236,6 +236,10 @@ void WorkspaceManager::SetActiveWorkspaceByWindow(Window* window) {
   }
 }
 
+Window* WorkspaceManager::GetActiveWorkspaceWindow() {
+  return active_workspace_->window();
+}
+
 Window* WorkspaceManager::GetParentForNewWindow(Window* window) {
   // Try to put windows with transient parents in the same workspace as their
   // transient parent.