Refactor cc scrollbar layers to separate solid-color vs desktop.

cc/layers/scrollbar_layer_impl_base.h

+// Copyright 2013 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 CC_LAYERS_SCROLLBAR_LAYER_IMPL_BASE_H_
+#define CC_LAYERS_SCROLLBAR_LAYER_IMPL_BASE_H_
+
+#include "cc/base/cc_export.h"
+#include "cc/input/scrollbar.h"
+#include "cc/layers/layer_impl.h"
+
+namespace cc {
+
+class LayerTreeImpl;
+
+class CC_EXPORT ScrollbarLayerImplBase : public LayerImpl {
+ public:
+  int ScrollLayerId() const { return scroll_layer_id_; }
+  void set_scroll_layer_id(int id) { scroll_layer_id_ = id; }
+
+  float current_pos() const { return current_pos_; }
+  void SetCurrentPos(float current_pos);
+  int maximum() const { return maximum_; }
+  void SetMaximum(int maximum);
+
+  void SetVerticalAdjust(float vertical_adjust);
+
+  bool is_overlay_scrollbar() const { return is_overlay_scrollbar_; }
+  void set_is_overlay_scrollbar(bool is_overlay) {
+    is_overlay_scrollbar_ = is_overlay;
+  }
+
+  ScrollbarOrientation orientation() const { return orientation_; }
+
+  virtual void PushPropertiesTo(LayerImpl* layer) OVERRIDE;
+  virtual ScrollbarLayerImplBase* ToScrollbarLayer() OVERRIDE;
+
+  void SetVisibleToTotalLengthRatio(float ratio);
+  virtual gfx::Rect ComputeThumbQuadRect() const;
+
+ protected:
+  ScrollbarLayerImplBase(LayerTreeImpl* tree_impl,
+                         int id,
+                         ScrollbarOrientation orientation);
+  virtual ~ScrollbarLayerImplBase() {}
+
+  gfx::Rect ScrollbarLayerRectToContentRect(gfx::RectF layer_rect) const;
+
+  float visible_to_total_length_ratio() const {
+    return visible_to_total_length_ratio_;
+  }
+  float vertical_adjust() const { return vertical_adjust_; }
+
+  virtual int ThumbThickness() const = 0;
+  virtual int ThumbLength() const = 0;
+  virtual float TrackLength() const = 0;
+  virtual int TrackStart() const = 0;
+
+ private:
+  int scroll_layer_id_;
+  bool is_overlay_scrollbar_;
+
+  float current_pos_;
+  int maximum_;
+  ScrollbarOrientation orientation_;
+
+  // Difference between the clip layer's height and the visible viewport
+  // height (which may differ in the presence of top-controls hiding).
+  float vertical_adjust_;
+
+  float visible_to_total_length_ratio_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScrollbarLayerImplBase);
+};
+
+}  // namespace cc
+
+#endif  // CC_LAYERS_SCROLLBAR_LAYER_IMPL_BASE_H_