Remove explicit keyword from multi-argument constructors

chrome/browser/upgrade_detector_impl.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/upgrade_detector_impl.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 45 matching lines @@
     return interval_ms * 1000;  // Command line value is in seconds.
 
   return kCheckForUpgradeMs;
 }
 
 // This task checks the currently running version of Chrome against the
 // installed version. If the installed version is newer, it runs the passed
 // callback task. Otherwise it just deletes the task.
 class DetectUpgradeTask : public Task {
  public:
-  explicit DetectUpgradeTask(Task* upgrade_detected_task,
-                             bool* is_unstable_channel)
+  DetectUpgradeTask(Task* upgrade_detected_task, bool* is_unstable_channel)
       : upgrade_detected_task_(upgrade_detected_task),
         is_unstable_channel_(is_unstable_channel) {
   }
 
   virtual ~DetectUpgradeTask() {
     if (upgrade_detected_task_) {
       // This has to get deleted on the same thread it was created.
       BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
                               new DeleteTask<Task>(upgrade_detected_task_));
     }
@@ skipping 177 matching lines @@
 
 // static
 UpgradeDetectorImpl* UpgradeDetectorImpl::GetInstance() {
   return Singleton<UpgradeDetectorImpl>::get();
 }
 
 // static
 UpgradeDetector* UpgradeDetector::GetInstance() {
   return UpgradeDetectorImpl::GetInstance();
 }