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

chrome/browser/ui/webui/fileicon_source.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 CHROME_BROWSER_UI_WEBUI_FILEICON_SOURCE_H_
 #define CHROME_BROWSER_UI_WEBUI_FILEICON_SOURCE_H_
 
 #include <string>
 
 #include "base/file_path.h"
 #include "chrome/browser/icon_manager.h"
 #include "chrome/browser/ui/webui/chrome_url_data_manager.h"
 #include "chrome/common/cancelable_task_tracker.h"
 #include "ui/base/layout.h"
 
 namespace gfx {
 class Image;
 }
 
 // FileIconSource is the gateway between network-level chrome:
 // requests for favicons and the history backend that serves these.
 class FileIconSource : public ChromeURLDataManager::DataSource {
  public:
-  explicit FileIconSource();
+  FileIconSource();
 
   // Called when the network layer has requested a resource underneath
   // the path we registered.
   virtual void StartDataRequest(const std::string& path,
                                 bool is_incognito,
                                 int request_id) OVERRIDE;
 
   virtual std::string GetMimeType(const std::string&) const OVERRIDE;
 
  protected:
@@ skipping 20 matching lines @@
   // Called when favicon data is available from the history backend.
   void OnFileIconDataAvailable(const IconRequestDetails& details,
                                gfx::Image* icon);
 
   // Tracks tasks requesting file icons.
   CancelableTaskTracker cancelable_task_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(FileIconSource);
 };
 #endif  // CHROME_BROWSER_UI_WEBUI_FILEICON_SOURCE_H_