Fix clang build break

chrome/browser/chromeos/input_method/input_method_engine.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_ENGINE_H_
 #define CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_ENGINE_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 namespace chromeos {
 
 extern const char* kExtensionImePrefix;
 
 // InputMethodEngine is used to translate from the Chrome IME API to the native
 // API.
 class InputMethodEngine {
  public:
   struct KeyboardEvent {
+    KeyboardEvent();
+    virtual ~KeyboardEvent();
+
     std::string type;
     std::string key;
     std::string key_code;
     bool alt_key;
     bool ctrl_key;
     bool shift_key;
   };
 
   struct MenuItem {
+    MenuItem();
+    virtual ~MenuItem();
+
     std::string id;
     std::string label;
     int style;
     bool visible;
     bool enabled;
     bool checked;
     std::string icon;
     KeyboardEvent shortcut_key;
     std::vector<MenuItem> children;
   };
 
   struct InputContext {
     int id;
     std::string type;
   };
 
   struct Candidate {
+    Candidate();
+    virtual ~Candidate();
+
     std::string value;
     int id;
     std::string label;
     std::string annotation;
     std::vector<Candidate> candidates;
   };
 
   struct SegmentInfo {
     int start;
     int end;
@@ skipping 115 matching lines @@
       const char* description,
       const char* language,
       const std::vector<std::string>& layouts,
       KeyboardEvent& shortcut_key,
       std::string* error);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_ENGINE_H_