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

ui/wm/core/shadow_controller.h

Index: ui/wm/core/shadow_controller.h
diff --git a/ui/wm/core/shadow_controller.h b/ui/wm/core/shadow_controller.h
index 360a9976a5f64e0cd5793904c9e6d224848588bb..b307c02e77697407ee7ac25cb4952b7ae16529b3 100644
--- a/ui/wm/core/shadow_controller.h
+++ b/ui/wm/core/shadow_controller.h
@@ -51,8 +51,10 @@ class WM_EXPORT ShadowController :
   ~ShadowController() 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;
 
  private:
   class Impl;