Remove GraphicsLayer::didScroll and directly call ScrollableArea::didScroll

third_party/WebKit/Source/platform/scroll/ScrollableArea.h

Index: third_party/WebKit/Source/platform/scroll/ScrollableArea.h
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
index 3d6fced85e3a0b3b47dc4a4680b0b23c326cc15d..d84ded405aa30807718da9ecbf10b73249017cd5 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollableArea.h
@@ -35,6 +35,7 @@
 #include "platform/scroll/ScrollAnimatorBase.h"
 #include "platform/scroll/ScrollTypes.h"
 #include "platform/scroll/Scrollbar.h"
+#include "public/platform/WebLayerScrollClient.h"
 #include "wtf/MathExtras.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/Vector.h"
@@ -59,7 +60,8 @@ enum IncludeScrollbarsInRect {
   IncludeScrollbars,
 };
 
-class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin {
+class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin,
+                                       public WebLayerScrollClient {
   WTF_MAKE_NONCOPYABLE(ScrollableArea);
 
  public:
@@ -372,6 +374,9 @@ class PLATFORM_EXPORT ScrollableArea : public GarbageCollectedMixin {
   // Ideally a frame-specific throttled one can be used.
   virtual RefPtr<WebTaskRunner> getTimerTaskRunner() const = 0;
 
+  // Callback for compositor-side scrolling.
+  void didScroll(const gfx::ScrollOffset&) override;
+
  protected:
   ScrollableArea();