Make scrollAnimatorEnabled work on Mac like it does on other platforms

content/renderer/render_thread_impl.cc

 // Copyright (c) 2012 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 "content/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <utility>
@@ skipping 1939 matching lines @@
 void RenderThreadImpl::OnUpdateScrollbarTheme(
     const ViewMsg_UpdateScrollbarTheme_Params& params) {
   EnsureWebKitInitialized();
   static_cast<WebScrollbarBehaviorImpl*>(
       blink_platform_impl_->scrollbarBehavior())
       ->set_jump_on_track_click(params.jump_on_track_click);
 
   blink::WebScrollbarTheme::updateScrollbarsWithNSDefaults(
       params.initial_button_delay, params.autoscroll_button_delay,
       params.preferred_scroller_style, params.redraw,
-      params.scroll_animation_enabled, params.button_placement);
+      params.button_placement);
 }
 
 void RenderThreadImpl::OnSystemColorsChanged(
     int aqua_color_variant,
     const std::string& highlight_text_color,
     const std::string& highlight_color) {
   SystemColorsDidChange(aqua_color_variant, highlight_text_color,
                         highlight_color);
 }
 #endif
@@ skipping 175 matching lines @@
 }
 
 void RenderThreadImpl::PendingRenderFrameConnect::OnConnectionError() {
   size_t erased =
       RenderThreadImpl::current()->pending_render_frame_connects_.erase(
           routing_id_);
   DCHECK_EQ(1u, erased);
 }
 
 }  // namespace content