Move SecurityInterstitialPage into component

chrome/browser/interstitials/security_interstitial_page_test_utils.h

 // Copyright 2015 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_INTERSTITIALS_SECURITY_INTERSTITIAL_PAGE_TEST_UTILS_H_
 #define CHROME_BROWSER_INTERSTITIALS_SECURITY_INTERSTITIAL_PAGE_TEST_UTILS_H_
 
 #include <string>
 
 #include "chrome/test/base/in_process_browser_test.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace content {
 class InterstitialPage;
 class WebContents;
 }
 
 class GURL;
+
+namespace security_interstitials {
 class SecurityInterstitialPage;
+}
 
 namespace chrome_browser_interstitials {
 
 bool IsInterstitialDisplayingText(
     const content::InterstitialPage* const interstitial,
     const std::string& text);
 
 // This class is used for testing the display of IDN names in security
 // interstitials.
 class SecurityInterstitialIDNTest : public InProcessBrowserTest {
  public:
   // InProcessBrowserTest implementation
   void SetUpOnMainThread() override;
 
   // Run a test that creates an interstitial with an IDN request URL
   // and checks that it is properly decoded.
   testing::AssertionResult VerifyIDNDecoded() const;
 
  protected:
-  virtual SecurityInterstitialPage* CreateInterstitial(
+  virtual security_interstitials::SecurityInterstitialPage* CreateInterstitial(
       content::WebContents* contents,
       const GURL& request_url) const = 0;
 };
 
 }  // namespace chrome_browser_interstitials
 
 #endif  // CHROME_BROWSER_INTERSTITIALS_SECURITY_INTERSTITIAL_PAGE_TEST_UTILS_H_