Implement position: sticky updates on compositor

cc/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 
 component("cc") {
   sources = [
     "animation/animation.cc",
@@ skipping 122 matching lines @@
     "layers/layer_impl.h",
     "layers/layer_impl_test_properties.cc",
     "layers/layer_impl_test_properties.h",
     "layers/layer_iterator.h",
     "layers/layer_list_iterator.cc",
     "layers/layer_list_iterator.h",
     "layers/layer_position_constraint.cc",
     "layers/layer_position_constraint.h",
     "layers/layer_proto_converter.cc",
     "layers/layer_proto_converter.h",
+    "layers/layer_sticky_position_constraint.cc",
+    "layers/layer_sticky_position_constraint.h",
     "layers/layer_utils.cc",
     "layers/layer_utils.h",
     "layers/nine_patch_layer.cc",
     "layers/nine_patch_layer.h",
     "layers/nine_patch_layer_impl.cc",
     "layers/nine_patch_layer_impl.h",
     "layers/paint_properties.h",
     "layers/painted_scrollbar_layer.cc",
     "layers/painted_scrollbar_layer.h",
     "layers/painted_scrollbar_layer_impl.cc",
@@ skipping 902 matching lines @@
     "//ui/gl:test_support",
   ]
 
   # This target should not require the Chrome executable to run.
   assert_no_deps = [ "//chrome" ]
 
   data = [
     "test/data/",
   ]
 }