Added an ActivationReason parameter to ActivationChangeObserver::OnWindowActivated(...).

ash/wm/workspace/workspace_layout_manager.h

Index: ash/wm/workspace/workspace_layout_manager.h
diff --git a/ash/wm/workspace/workspace_layout_manager.h b/ash/wm/workspace/workspace_layout_manager.h
index 5570dd53ac87347a8eeae2f60615ffb31573b12d..d5e57ec0d0ec9b54154d753e9abe77d0360d82fb 100644
--- a/ash/wm/workspace/workspace_layout_manager.h
+++ b/ash/wm/workspace/workspace_layout_manager.h
@@ -84,8 +84,10 @@ class ASH_EXPORT WorkspaceLayoutManager
                              const gfx::Rect& new_bounds) override;
 
   // aura::client::ActivationChangeObserver overrides:
-  void OnWindowActivated(aura::Window* gained_active,
-                         aura::Window* lost_active) override;
+  void OnWindowActivated(
+      aura::client::ActivationChangeObserver::ActivationReason reason,
+      aura::Window* gained_active,
+      aura::Window* lost_active) override;
 
   // keyboard::KeyboardControllerObserver overrides:
   void OnKeyboardBoundsChanging(const gfx::Rect& new_bounds) override;