Remove ScrollableArea and Scrollbar

sky/engine/public/platform/WebFallbackThemeEngine.h

Index: sky/engine/public/platform/WebFallbackThemeEngine.h
diff --git a/sky/engine/public/platform/WebFallbackThemeEngine.h b/sky/engine/public/platform/WebFallbackThemeEngine.h
index aa19b962f924b51b77498e5551a9c3b916df2c0f..2bb1cc334de3a69980e6e16a6e1a98ccf86a2f8a 100644
--- a/sky/engine/public/platform/WebFallbackThemeEngine.h
+++ b/sky/engine/public/platform/WebFallbackThemeEngine.h
@@ -43,16 +43,6 @@ class WebFallbackThemeEngine {
 public:
     // The UI part which is being accessed.
     enum Part {
-        // ScrollbarTheme parts
-        PartScrollbarDownArrow,
-        PartScrollbarLeftArrow,
-        PartScrollbarRightArrow,
-        PartScrollbarUpArrow,
-        PartScrollbarHorizontalThumb,
-        PartScrollbarVerticalThumb,
-        PartScrollbarHorizontalTrack,
-        PartScrollbarVerticalTrack,
-
         // RenderTheme parts
         PartCheckbox,
         PartRadio,
@@ -72,16 +62,6 @@ public:
         StatePressed,
     };
 
-    // Extra parameters for drawing the PartScrollbarHorizontalTrack and
-    // PartScrollbarVerticalTrack.
-    struct ScrollbarTrackExtraParams {
-        // The bounds of the entire track, as opposed to the part being painted.
-        int trackX;
-        int trackY;
-        int trackWidth;
-        int trackHeight;
-    };
-
     // Extra parameters for PartCheckbox, PartPushButton and PartRadio.
     struct ButtonExtraParams {
         bool checked;
@@ -122,7 +102,6 @@ public:
     };
 
     union ExtraParams {
-        ScrollbarTrackExtraParams scrollbarTrack;
         ButtonExtraParams button;
         MenuListExtraParams menuList;
         SliderExtraParams slider;