Add back the truncation of scroll_delta

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 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 "cc/trees/layer_tree_host_impl.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/basictypes.h"
@@ skipping 2992 matching lines @@
 static void CollectScrollDeltas(ScrollAndScaleSet* scroll_info,
                                 LayerImpl* layer_impl) {
   if (!layer_impl)
     return;
 
   gfx::ScrollOffset scroll_delta = layer_impl->PullDeltaForMainThread();
 
   if (!scroll_delta.IsZero()) {
     LayerTreeHostCommon::ScrollUpdateInfo scroll;
     scroll.layer_id = layer_impl->id();
-    scroll.scroll_delta = gfx::Vector2dF(scroll_delta.x(), scroll_delta.y());
+    scroll.scroll_delta = gfx::Vector2d(scroll_delta.x(), scroll_delta.y());
     scroll_info->scrolls.push_back(scroll);
   }
 
   for (size_t i = 0; i < layer_impl->children().size(); ++i)
     CollectScrollDeltas(scroll_info, layer_impl->children()[i]);
 }
 
 scoped_ptr<ScrollAndScaleSet> LayerTreeHostImpl::ProcessScrollDeltas() {
   scoped_ptr<ScrollAndScaleSet> scroll_info(new ScrollAndScaleSet());
 
@@ skipping 443 matching lines @@
   new_target.SetToMin(layer_impl->MaxScrollOffset());
 
   curve->UpdateTarget(
       animation->TrimTimeToCurrentIteration(CurrentBeginFrameArgs().frame_time)
           .InSecondsF(),
       new_target);
 
   return true;
 }
 }  // namespace cc