cc: Move SyncedScrollOffset to scroll tree

cc/layers/layer_iterator_unittest.cc

 // Copyright 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 "cc/layers/layer_iterator.h"
 
 #include <vector>
 
 #include "cc/layers/layer.h"
 #include "cc/test/fake_layer_tree_host.h"
@@ skipping 17 matching lines @@
     return make_scoped_ptr(new TestLayerImpl(tree, id));
   }
   ~TestLayerImpl() override {}
 
   int count_representing_target_surface_;
   int count_representing_contributing_surface_;
   int count_representing_itself_;
 
  private:
   explicit TestLayerImpl(LayerTreeImpl* tree, int id)
-      : LayerImpl(tree, id, new SyncedScrollOffset),
+      : LayerImpl(tree, id),
         count_representing_target_surface_(-1),
         count_representing_contributing_surface_(-1),
         count_representing_itself_(-1) {
     SetBounds(gfx::Size(100, 100));
     SetPosition(gfx::PointF());
     SetDrawsContent(true);
   }
 };
 
 #define EXPECT_COUNT(layer, target, contrib, itself)                           \
@@ skipping 204 matching lines @@
   EXPECT_COUNT(root21_ptr, -1, -1, 9);
   EXPECT_COUNT(root22_ptr, 7, 8, 6);
   EXPECT_COUNT(root221_ptr, -1, -1, 5);
   EXPECT_COUNT(root23_ptr, 3, 4, 2);
   EXPECT_COUNT(root231_ptr, -1, -1, 1);
   EXPECT_COUNT(root3_ptr, -1, -1, 0);
 }
 
 }  // namespace
 }  // namespace cc