Makes sure that an input method doesn't reference to a destroyed object.

ui/base/ime/mock_input_method.h

Index: ui/base/ime/mock_input_method.h
diff --git a/ui/base/ime/mock_input_method.h b/ui/base/ime/mock_input_method.h
index fdeff5ee8ce413120b858f5664977cfd636fc998..1d7922f59363e800158b221d41f3c12b3288c084 100644
--- a/ui/base/ime/mock_input_method.h
+++ b/ui/base/ime/mock_input_method.h
@@ -49,6 +49,7 @@ class UI_EXPORT MockInputMethod : NON_EXPORTED_BASE(public InputMethod) {
   virtual bool OnUntranslatedIMEMessage(const base::NativeEvent& event,
                                         NativeEventResult* result) OVERRIDE;
   virtual void SetFocusedTextInputClient(TextInputClient* client) OVERRIDE;
+  virtual void DetachTextInputClient(TextInputClient* client) OVERRIDE;
   virtual TextInputClient* GetTextInputClient() const OVERRIDE;
   virtual bool DispatchKeyEvent(const base::NativeEvent& native_event) OVERRIDE;
   virtual bool DispatchFabricatedKeyEvent(const ui::KeyEvent& event) OVERRIDE;