chrome: Cleanup class/struct forward declarations

chrome/browser/safe_browsing/safe_browsing_blocking_page.h

 // Copyright (c) 2012 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.
 //
 // Classes for managing the SafeBrowsing interstitial pages.
 //
 // When a user is about to visit a page the SafeBrowsing system has deemed to
 // be malicious, either as malware or a phishing page, we show an interstitial
 // page with some options (go back, continue) to give the user a chance to avoid
 // the harmful page.
@@ skipping 25 matching lines @@
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "chrome/browser/interstitials/chrome_metrics_helper.h"
 #include "chrome/browser/interstitials/security_interstitial_page.h"
 #include "chrome/browser/safe_browsing/ui_manager.h"
 #include "content/public/browser/interstitial_page_delegate.h"
 #include "url/gurl.h"
 
-namespace base {
-class MessageLoop;
-}
-
 namespace safe_browsing {
 
 class SafeBrowsingBlockingPageFactory;
 class ThreatDetails;
 
 class SafeBrowsingBlockingPage : public SecurityInterstitialPage {
  public:
   typedef SafeBrowsingUIManager::UnsafeResource UnsafeResource;
   typedef std::vector<UnsafeResource> UnsafeResourceList;
   typedef std::map<content::WebContents*, UnsafeResourceList> UnsafeResourceMap;
@@ skipping 177 matching lines @@
   virtual SafeBrowsingBlockingPage* CreateSafeBrowsingPage(
       SafeBrowsingUIManager* ui_manager,
       content::WebContents* web_contents,
       const GURL& main_frame_url,
       const SafeBrowsingBlockingPage::UnsafeResourceList& unsafe_resources) = 0;
 };
 
 }  // namespace safe_browsing
 
 #endif  // CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_BLOCKING_PAGE_H_