views: Mark single-argument constructors as explicit.

ui/views/controls/combobox/native_combobox_views_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/utf_string_conversions.h"
 #include "ui/base/keycodes/keyboard_codes.h"
 #include "ui/base/models/combobox_model.h"
 #include "ui/views/controls/combobox/combobox.h"
 #include "ui/views/controls/combobox/native_combobox_views.h"
 #include "ui/views/ime/mock_input_method.h"
 #include "ui/views/test/views_test_base.h"
 #include "ui/views/widget/native_widget_private.h"
 #include "ui/views/widget/widget.h"
 
 namespace {
 
 // A wrapper of Combobox to intercept the result of OnKeyPressed() and
 // OnKeyReleased() methods.
 class TestCombobox : public views::Combobox {
  public:
-  TestCombobox(ui::ComboboxModel* model)
+  explicit TestCombobox(ui::ComboboxModel* model)
       : Combobox(model),
         key_handled_(false),
         key_received_(false) {
   }
 
   virtual bool OnKeyPressed(const views::KeyEvent& e) OVERRIDE {
     key_received_ = true;
     key_handled_ = views::Combobox::OnKeyPressed(e);
     return key_handled_;
   }
@@ skipping 154 matching lines @@
   widget_->SetContentsView(container);
   container->AddChildView(combobox_);
 
   combobox_view_ = static_cast<NativeComboboxViews*>(
       combobox_->GetNativeWrapperForTesting());
   ASSERT_TRUE(combobox_view_);
   ASSERT_FALSE(combobox_view_->enabled());
 }
 
 }  // namespace views