Use float for scroll offset.

cc/blink/web_layer_impl.h

Index: cc/blink/web_layer_impl.h
diff --git a/cc/blink/web_layer_impl.h b/cc/blink/web_layer_impl.h
index eaa2f05ae98da211c3d1cea1a09cdd581df94df0..010eac20a654dd97ad245bb2754868f64489601a 100644
--- a/cc/blink/web_layer_impl.h
+++ b/cc/blink/web_layer_impl.h
@@ -99,8 +99,8 @@ class CC_BLINK_EXPORT WebLayerImpl : public NON_EXPORTED_BASE(blink::WebLayer) {
   void setFiltersOrigin(const blink::WebFloatPoint& origin) override;
   void setBackgroundFilters(const cc::FilterOperations& filters) override;
   bool hasActiveAnimationForTesting() override;
-  void setScrollPositionDouble(blink::WebDoublePoint position) override;
-  blink::WebDoublePoint scrollPositionDouble() const override;
+  void setScrollOffset(blink::WebFloatSize position) override;
+  blink::WebFloatSize scrollOffset() const override;
   void setScrollClipLayer(blink::WebLayer* clip_layer) override;
   bool scrollable() const override;
   void setUserScrollable(bool horizontal, bool vertical) override;