Extract content dependency from keyboard code

ash/test/test_shell_delegate.h

Index: ash/test/test_shell_delegate.h
diff --git a/ash/test/test_shell_delegate.h b/ash/test/test_shell_delegate.h
index 3cbf58d38685810be9d91235affc703740e2bea4..3bf7cef2bc6940e62e464b20eb532fb8781cdb80 100644
--- a/ash/test/test_shell_delegate.h
+++ b/ash/test/test_shell_delegate.h
@@ -15,7 +15,7 @@
 #include "base/observer_list.h"
 
 namespace keyboard {
-class KeyboardControllerProxy;
+class KeyboardUI;
 }
 
 namespace ash {
@@ -41,7 +41,7 @@ class TestShellDelegate : public ShellDelegate {
   void PreInit() override;
   void PreShutdown() override;
   void Exit() override;
-  keyboard::KeyboardControllerProxy* CreateKeyboardControllerProxy() override;
+  keyboard::KeyboardUI* CreateKeyboardUI() override;
   void VirtualKeyboardActivated(bool activated) override;
   void AddVirtualKeyboardStateObserver(
       VirtualKeyboardStateObserver* observer) override;