Use float for scroll offset.

third_party/WebKit/Source/platform/graphics/CompositorMutableState.cpp

 // Copyright 2016 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.
 
 #include "platform/graphics/CompositorMutableState.h"
 
 #include "cc/layers/layer_impl.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "platform/graphics/CompositorMutation.h"
 
@@ skipping 27 matching lines @@
   if (!m_mainLayer)
     return;
   m_mainLayer->layer_tree_impl()
       ->property_trees()
       ->transform_tree.OnTransformAnimated(gfx::Transform(matrix),
                                            m_mainLayer->transform_tree_index(),
                                            m_mainLayer->layer_tree_impl());
   m_mutation->setTransform(matrix);
 }
 
-double CompositorMutableState::scrollLeft() const {
+float CompositorMutableState::scrollLeft() const {
   return m_scrollLayer ? m_scrollLayer->CurrentScrollOffset().x() : 0.0;
 }
 
-void CompositorMutableState::setScrollLeft(double scrollLeft) {
+void CompositorMutableState::setScrollLeft(float scrollLeft) {
   if (!m_scrollLayer)
     return;
 
   gfx::ScrollOffset offset = m_scrollLayer->CurrentScrollOffset();
   offset.set_x(scrollLeft);
   m_scrollLayer->layer_tree_impl()
       ->property_trees()
       ->scroll_tree.OnScrollOffsetAnimated(
           m_scrollLayer->id(), m_scrollLayer->transform_tree_index(),
           m_scrollLayer->scroll_tree_index(), offset,
           m_scrollLayer->layer_tree_impl());
   m_mutation->setScrollLeft(scrollLeft);
 }
 
-double CompositorMutableState::scrollTop() const {
+float CompositorMutableState::scrollTop() const {
   return m_scrollLayer ? m_scrollLayer->CurrentScrollOffset().y() : 0.0;
 }
 
-void CompositorMutableState::setScrollTop(double scrollTop) {
+void CompositorMutableState::setScrollTop(float scrollTop) {
   if (!m_scrollLayer)
     return;
   gfx::ScrollOffset offset = m_scrollLayer->CurrentScrollOffset();
   offset.set_y(scrollTop);
   m_scrollLayer->layer_tree_impl()
       ->property_trees()
       ->scroll_tree.OnScrollOffsetAnimated(
           m_scrollLayer->id(), m_scrollLayer->transform_tree_index(),
           m_scrollLayer->scroll_tree_index(), offset,
           m_scrollLayer->layer_tree_impl());
   m_mutation->setScrollTop(scrollTop);
 }
 
 }  // namespace blink