Add a flag for enabling compositor property trees

ui/compositor/compositor.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 "ui/compositor/compositor.h"
 
 #include <algorithm>
 #include <deque>
 
 #include "base/bind.h"
@@ skipping 117 matching lines @@
   settings.initial_debug_state.show_surface_damage_rects =
       command_line->HasSwitch(cc::switches::kUIShowSurfaceDamageRects);
   settings.initial_debug_state.show_screen_space_rects =
       command_line->HasSwitch(cc::switches::kUIShowScreenSpaceRects);
   settings.initial_debug_state.show_replica_screen_space_rects =
       command_line->HasSwitch(cc::switches::kUIShowReplicaScreenSpaceRects);
 
   settings.initial_debug_state.SetRecordRenderingStats(
       command_line->HasSwitch(cc::switches::kEnableGpuBenchmarking));
 
+  settings.use_property_trees =
+      command_line->HasSwitch(cc::switches::kEnableCompositorPropertyTrees);
   settings.use_zero_copy = IsUIZeroCopyEnabled();
 
   settings.renderer_settings.use_rgba_4444_textures =
       command_line->HasSwitch(switches::kUIEnableRGBA4444Textures);
 
   // UI compositor always uses partial raster if not using zero-copy. Zero copy
   // doesn't currently support partial raster.
   settings.use_partial_raster = !settings.use_zero_copy;
 
   // Use CPU_READ_WRITE_PERSISTENT memory buffers to support partial tile
@@ skipping 344 matching lines @@
                     observer_list_,
                     OnCompositingLockStateChanged(this));
 }
 
 void Compositor::CancelCompositorLock() {
   if (compositor_lock_)
     compositor_lock_->CancelLock();
 }
 
 }  // namespace ui