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

dbus/mock_bus.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 DBUS_MOCK_BUS_H_
 #define DBUS_MOCK_BUS_H_
 
 #include "dbus/bus.h"
 #include "dbus/object_path.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace dbus {
 
 // Mock for Bus class. Along with MockObjectProxy and MockExportedObject,
 // the mock classes can be used to write unit tests without issuing real
 // D-Bus calls.
 class MockBus : public Bus {
  public:
-  MockBus(Bus::Options& options);
+  explicit MockBus(Bus::Options& options);
 
   MOCK_METHOD2(GetObjectProxy, ObjectProxy*(const std::string& service_name,
                                             const ObjectPath& object_path));
   MOCK_METHOD3(GetObjectProxyWithOptions,
                ObjectProxy*(const std::string& service_name,
                             const ObjectPath& object_path,
                             int options));
   MOCK_METHOD1(GetExportedObject, ExportedObject*(
       const ObjectPath& object_path));
   MOCK_METHOD0(ShutdownAndBlock, void());
@@ skipping 40 matching lines @@
   MOCK_METHOD0(AssertOnOriginThread, void());
   MOCK_METHOD0(AssertOnDBusThread, void());
 
  protected:
   virtual ~MockBus();
 };
 
 }  // namespace dbus
 
 #endif  // DBUS_MOCK_BUS_H_