Fullscreen backdrop window for maximize mode

ash/common/wm/maximize_mode/workspace_backdrop_delegate.h

Index: ash/common/wm/maximize_mode/workspace_backdrop_delegate.h
diff --git a/ash/common/wm/maximize_mode/workspace_backdrop_delegate.h b/ash/common/wm/maximize_mode/workspace_backdrop_delegate.h
index 4145c2cb4cfc69e798bfc37fc98b63d43a6ee728..60f72fbe34bdc6a51034e41ed4328f0816d96f14 100644
--- a/ash/common/wm/maximize_mode/workspace_backdrop_delegate.h
+++ b/ash/common/wm/maximize_mode/workspace_backdrop_delegate.h
@@ -35,25 +35,17 @@ class ASH_EXPORT WorkspaceBackdropDelegate
   void OnWindowStackingChanged(WmWindow* window) override;
   void OnPostWindowStateTypeChange(wm::WindowState* window_state,
                                    wm::WindowStateType old_type) override;
-  void OnDisplayWorkAreaInsetsChanged() override;
 
  private:
-  class WindowObserverImpl;
-
   // Restack the backdrop relatively to the other windows in the container.
   void RestackBackdrop();
 
   // Returns the current visible top level window in the container.
   WmWindow* GetCurrentTopWindow();
 
-  // Position & size the background over the container window.
-  void AdjustToContainerBounds();
-
   // Show the overlay.
   void Show();
 
-  std::unique_ptr<WindowObserverImpl> container_observer_;
-
   // The background which covers the rest of the screen.
   views::Widget* background_ = nullptr;
   // WmWindow for |background_|.