Add missing (and remove superfluous) 'explicit' from constructors.

content/browser/download/download_manager_impl.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.
 
 #ifndef CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_IMPL_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_IMPL_H_
 
 #include <map>
 #include <set>
 
@@ skipping 15 matching lines @@
 namespace content {
 class DownloadFileFactory;
 class DownloadItemFactory;
 class DownloadItemImpl;
 
 class CONTENT_EXPORT DownloadManagerImpl : public DownloadManager,
                                            private DownloadItemImplDelegate {
  public:
   // Caller guarantees that |net_log| will remain valid
   // for the lifetime of DownloadManagerImpl (until Shutdown() is called).
-  DownloadManagerImpl(net::NetLog* net_log);
+  explicit DownloadManagerImpl(net::NetLog* net_log);
 
   // Implementation functions (not part of the DownloadManager interface).
 
   // Creates a download item for the SavePackage system.
   // Must be called on the UI thread.  Note that the DownloadManager
   // retains ownership.
   virtual DownloadItemImpl* CreateSavePackageDownloadItem(
       const FilePath& main_file_path,
       const GURL& page_url,
       const std::string& mime_type,
@@ skipping 111 matching lines @@
   DownloadManagerDelegate* delegate_;
 
   net::NetLog* net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadManagerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_MANAGER_IMPL_H_