Enable strict-virtual-specifiers for iOS builds.

ios/web/public/test/test_web_state.h

 // Copyright 2014 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 IOS_WEB_PUBLIC_TEST_TEST_WEB_STATE_H_
 #define IOS_WEB_PUBLIC_TEST_TEST_WEB_STATE_H_
 
 #include <string>
 
 #include "ios/web/public/web_state/web_state.h"
 #include "url/gurl.h"
 
 namespace web {
 
 // Minimal implementation of WebState, to be used in tests.
 class TestWebState : public WebState {
  public:
   // WebState implementation.
-  virtual BrowserState* GetBrowserState() const override;
-  virtual void OpenURL(const OpenURLParams& params) override {}
-  virtual NavigationManager* GetNavigationManager() override;
-  virtual CRWJSInjectionReceiver* GetJSInjectionReceiver() const override;
-  virtual const std::string& GetContentsMimeType() const override;
-  virtual const std::string& GetContentLanguageHeader() const override;
-  virtual bool ContentIsHTML() const override;
-  virtual const GURL& GetVisibleURL() const override;
-  virtual const GURL& GetLastCommittedURL() const override;
-  virtual void AddScriptCommandCallback(
-      const ScriptCommandCallback& callback,
-      const std::string& command_prefix) override {}
-  virtual void RemoveScriptCommandCallback(
-      const std::string& command_prefix) override {}
-  virtual void AddObserver(WebStateObserver* observer) override {}
-  virtual void RemoveObserver(WebStateObserver* observer) override {}
+  BrowserState* GetBrowserState() const override;
+  void OpenURL(const OpenURLParams& params) override {}
+  NavigationManager* GetNavigationManager() override;
+  CRWJSInjectionReceiver* GetJSInjectionReceiver() const override;
+  const std::string& GetContentsMimeType() const override;
+  const std::string& GetContentLanguageHeader() const override;
+  bool ContentIsHTML() const override;
+  const GURL& GetVisibleURL() const override;
+  const GURL& GetLastCommittedURL() const override;
+  void AddScriptCommandCallback(const ScriptCommandCallback& callback,
+                                const std::string& command_prefix) override {}
+  void RemoveScriptCommandCallback(const std::string& command_prefix) override {
+  }
+  void AddObserver(WebStateObserver* observer) override {}
+  void RemoveObserver(WebStateObserver* observer) override {}
 
  private:
   GURL url_;
   std::string mime_type_;
   std::string content_language_;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_PUBLIC_TEST_TEST_WEB_STATE_H_