Media Controls: move timeline related code to modules.

third_party/WebKit/Source/core/layout/api/LayoutSliderItem.h

-
 // Copyright 2016 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 LayoutSliderItem_h
 #define LayoutSliderItem_h
 
+#include "core/CoreExport.h"
 #include "core/layout/LayoutSlider.h"
 #include "core/layout/api/LayoutBlockItem.h"
 
 namespace blink {
 
 class LayoutSliderItem : public LayoutBlockItem {
  public:
   explicit LayoutSliderItem(LayoutSlider* layout_slider)
       : LayoutBlockItem(layout_slider) {}
 
   explicit LayoutSliderItem(const LayoutBlockItem& item)
       : LayoutBlockItem(item) {
     SECURITY_DCHECK(!item || item.IsSlider());
   }
 
   explicit LayoutSliderItem(std::nullptr_t) : LayoutBlockItem(nullptr) {}
 
-  LayoutSliderItem() {}
+  LayoutSliderItem() = default;
 
-  bool InDragMode() const { return ToSlider()->InDragMode(); }
+  CORE_EXPORT bool InDragMode() const { return ToSlider()->InDragMode(); }
 
  private:
   LayoutSlider* ToSlider() { return ToLayoutSlider(GetLayoutObject()); }
   const LayoutSlider* ToSlider() const {
     return ToLayoutSlider(GetLayoutObject());
   }
 };
 
 }  // namespace blink
 
 #endif  // LayoutSliderItem_h