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

content/browser/in_process_webkit/indexed_db_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/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "content/browser/browser_thread_impl.h"
 #include "content/browser/in_process_webkit/indexed_db_context_impl.h"
 #include "content/public/browser/storage_partition.h"
 #include "content/public/common/url_constants.h"
@@ skipping 116 matching lines @@
   message_loop_.RunUntilIdle();
 
   // No data was cleared because of SetForceKeepSessionState.
   EXPECT_TRUE(file_util::DirectoryExists(normal_path));
   EXPECT_TRUE(file_util::DirectoryExists(session_only_path));
 }
 
 class MockWebIDBDatabase : public WebKit::WebIDBDatabase
 {
  public:
-  MockWebIDBDatabase(bool expect_force_close)
+  explicit MockWebIDBDatabase(bool expect_force_close)
       : expect_force_close_(expect_force_close),
         force_close_called_(false) {}
 
   ~MockWebIDBDatabase()
   {
     EXPECT_TRUE(force_close_called_ == expect_force_close_);
   }
 
   virtual void forceClose()
   {
@@ skipping 46 matching lines @@
     message_loop_.RunUntilIdle();
   }
 
   // Make sure we wait until the destructor has run.
   message_loop_.RunUntilIdle();
 
   EXPECT_FALSE(file_util::DirectoryExists(test_path));
 }
 
 }  // namespace content