Revert "Add AppWindow.setVisibleOnAllWorkspaces." (https://codereview.chromium.org/469993003)

extensions/browser/app_window/app_window.h

Index: extensions/browser/app_window/app_window.h
diff --git a/extensions/browser/app_window/app_window.h b/extensions/browser/app_window/app_window.h
index a7378bd7323a274c33586f9ee7dc6c0f536140a4..f3b8e6ecbc4fbd9682f599b3a9954002dc86a676 100644
--- a/extensions/browser/app_window/app_window.h
+++ b/extensions/browser/app_window/app_window.h
@@ -180,9 +180,6 @@ class AppWindow : public content::NotificationObserver,
     // configured to be always on top. Defaults to false.
     bool always_on_top;
 
-    // If true, the window will be visible on all workspaces. Defaults to false.
-    bool visible_on_all_workspaces;
-
     // The API enables developers to specify content or window bounds. This
     // function combines them into a single, constrained window size.
     gfx::Rect GetInitialWindowBounds(const gfx::Insets& frame_insets) const;