MacViews: Overlay Scrollbars with Show/Hide Animations

ui/native_theme/native_theme.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 UI_NATIVE_THEME_NATIVE_THEME_H_
 #define UI_NATIVE_THEME_NATIVE_THEME_H_
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "build/build_config.h"
@@ skipping 79 matching lines @@
   // The state of the part.
   enum State {
     // IDs defined as specific values for use in arrays.
     kDisabled = 0,
     kHovered  = 1,
     kNormal   = 2,
     kPressed  = 3,
     kNumStates = kPressed + 1,
   };
 
+  // Struct that holds overlay information.
+  // If is_overlay is set to false, then the part is not overlay-styled
+  // and the alpha value should be ignored.
+  struct OverlayParams {
+    double alpha;
+    double is_overlay;

[tapted, 2016/02/08 00:31:15]

double -> bool?

[spqchan, 2016/02/09 21:21:25]

Whoops, done

+  };
+
   // Each structure below holds extra information needed when painting a given
   // part.
 
   struct ButtonExtraParams {
     bool checked;
     bool indeterminate;  // Whether the button state is indeterminate.
     bool is_default;  // Whether the button is default button.
     bool is_focused;
     bool has_border;
     int classic_state;  // Used on Windows when uxtheme is not available.
@@ skipping 43 matching lines @@
     double animated_seconds;
     bool determinate;
     int value_rect_x;
     int value_rect_y;
     int value_rect_width;
     int value_rect_height;
   };
 
   struct ScrollbarArrowExtraParams {
     bool is_hovering;
+    OverlayParams overlay;
   };
 
   struct ScrollbarTrackExtraParams {
     bool is_upper;
     int track_x;
     int track_y;
     int track_width;
     int track_height;
+    OverlayParams overlay;
     int classic_state;  // Used on Windows when uxtheme is not available.
   };
 
   struct ScrollbarThumbExtraParams {
     bool is_hovering;
+    OverlayParams overlay;
   };
 
   struct SliderExtraParams {
     bool vertical;
     bool in_drag;
   };
 
   struct TextFieldExtraParams {
     bool is_text_area;
     bool is_listbox;
@@ skipping 190 matching lines @@
  private:
   // Observers to notify when the native theme changes.
   base::ObserverList<NativeThemeObserver> native_theme_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeTheme);
 };
 
 }  // namespace ui
 
 #endif  // UI_NATIVE_THEME_NATIVE_THEME_H_