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

base/threading/thread_checker_unittest.cc

 // 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.
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "base/threading/simple_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 29 matching lines @@
   static void MethodOnDifferentThreadImpl();
   static void DetachThenCallFromDifferentThreadImpl();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ThreadCheckerClass);
 };
 
 // Calls ThreadCheckerClass::DoStuff on another thread.
 class CallDoStuffOnThread : public base::SimpleThread {
  public:
-  CallDoStuffOnThread(ThreadCheckerClass* thread_checker_class)
+  explicit CallDoStuffOnThread(ThreadCheckerClass* thread_checker_class)
       : SimpleThread("call_do_stuff_on_thread"),
         thread_checker_class_(thread_checker_class) {
   }
 
   virtual void Run() OVERRIDE {
     thread_checker_class_->DoStuff();
   }
 
  private:
   ThreadCheckerClass* thread_checker_class_;
 
   DISALLOW_COPY_AND_ASSIGN(CallDoStuffOnThread);
 };
 
 // Deletes ThreadCheckerClass on a different thread.
 class DeleteThreadCheckerClassOnThread : public base::SimpleThread {
  public:
-  DeleteThreadCheckerClassOnThread(ThreadCheckerClass* thread_checker_class)
+  explicit DeleteThreadCheckerClassOnThread(
+      ThreadCheckerClass* thread_checker_class)
       : SimpleThread("delete_thread_checker_class_on_thread"),
         thread_checker_class_(thread_checker_class) {
   }
 
   virtual void Run() OVERRIDE {
     thread_checker_class_.reset();
   }
 
  private:
   scoped_ptr<ThreadCheckerClass> thread_checker_class_;
@@ skipping 94 matching lines @@
   ThreadCheckerClass::DetachThenCallFromDifferentThreadImpl();
 }
 #endif  // ENABLE_THREAD_CHECKER
 
 #endif  // GTEST_HAS_DEATH_TEST || !ENABLE_THREAD_CHECKER
 
 // Just in case we ever get lumped together with other compilation units.
 #undef ENABLE_THREAD_CHECKER
 
 }  // namespace base