Use float for scroll offset.

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

Index: third_party/WebKit/Source/platform/scroll/ScrollAnimator.h
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollAnimator.h b/third_party/WebKit/Source/platform/scroll/ScrollAnimator.h
index 16a379106af6b1636b5c33a67767f0ab551c7e55..b8a9eabe167bc9da6e050d7289b2b6c27737971e 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollAnimator.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollAnimator.h
@@ -35,7 +35,6 @@
 #include "platform/animation/CompositorAnimationDelegate.h"
 #include "platform/animation/CompositorAnimationPlayerClient.h"
 #include "platform/animation/CompositorScrollOffsetAnimationCurve.h"
-#include "platform/geometry/FloatPoint.h"
 #include "platform/scroll/ScrollAnimatorBase.h"
 #include <memory>
 
@@ -51,17 +50,18 @@ class PLATFORM_EXPORT ScrollAnimator : public ScrollAnimatorBase {
   ~ScrollAnimator() override;
 
   bool hasRunningAnimation() const override;
-  FloatSize computeDeltaToConsume(const FloatSize& delta) const override;
+  ScrollOffset computeDeltaToConsume(const ScrollOffset& delta) const override;
 
-  ScrollResult userScroll(ScrollGranularity, const FloatSize& delta) override;
-  void scrollToOffsetWithoutAnimation(const FloatPoint&) override;
-  FloatPoint desiredTargetPosition() const override;
+  ScrollResult userScroll(ScrollGranularity,
+                          const ScrollOffset& delta) override;
+  void scrollToOffsetWithoutAnimation(const ScrollOffset&) override;
+  ScrollOffset desiredTargetOffset() const override;
 
   // ScrollAnimatorCompositorCoordinator implementation.
   void tickAnimation(double monotonicTime) override;
   void cancelAnimation() override;
-  void adjustAnimationAndSetScrollPosition(const DoublePoint& position,
-                                           ScrollType) override;
+  void adjustAnimationAndSetScrollOffset(const ScrollOffset&,
+                                         ScrollType) override;
   void takeOverCompositorAnimation() override;
   void resetAnimationState() override;
   void updateCompositorAnimations() override;
@@ -96,12 +96,12 @@ class PLATFORM_EXPORT ScrollAnimator : public ScrollAnimatorBase {
   void addMainThreadScrollingReason();
   void removeMainThreadScrollingReason();
 
-  // Returns true if will animate to the given target position. Returns false
+  // Returns true if will animate to the given target offset. Returns false
   // only when there is no animation running and we are not starting one
   // because we are already at targetPos.
-  bool willAnimateToOffset(const FloatPoint& targetPos);
+  bool willAnimateToOffset(const ScrollOffset& targetPos);
 
-  FloatPoint m_targetOffset;
+  ScrollOffset m_targetOffset;
   ScrollGranularity m_lastGranularity;
 };