try 3 of: Split out InputMethodMenuManager from InputMethodManager.

chrome/browser/chromeos/input_method/mock_input_method_engine.h

Index: chrome/browser/chromeos/input_method/mock_input_method_engine.h
diff --git a/chrome/browser/chromeos/input_method/mock_input_method_engine.h b/chrome/browser/chromeos/input_method/mock_input_method_engine.h
index b5ad032841560c3905cac5e3efecd56e20e60e5c..39e5647ce89791dd21c6da586edcc514cf8242b6 100644
--- a/chrome/browser/chromeos/input_method/mock_input_method_engine.h
+++ b/chrome/browser/chromeos/input_method/mock_input_method_engine.h
@@ -15,13 +15,18 @@ namespace ui {
 class KeyEvent;
 }  // namespace ui
 
+namespace ash {
+namespace ime {
+struct InputMethodMenuItem;
+}  // namespace ime
+}  // namespace ash
+
 namespace chromeos {
 
 class CompositionText;
 
 namespace input_method {
 class CandidateWindow;
-struct InputMethodProperty;
 struct KeyEventHandle;
 }  // namespace input_method