cc : Remove parent for mask and replica layers in LayerImpl

cc/trees/damage_tracker_unittest.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/damage_tracker.h"
 
 #include <stddef.h>
 
 #include "cc/base/math_util.h"
 #include "cc/layers/layer_impl.h"
@@ skipping 1374 matching lines @@
     scoped_ptr<LayerImpl> grand_child1_replica =
             LayerImpl::Create(host_impl_.active_tree(), 6);
     grand_child1_replica->SetPosition(gfx::PointF());
 
     // This is the anchor being tested.
     grand_child1_replica->SetTransformOrigin(
         gfx::Point3F(grand_child1->bounds().width(), 0.f, 0.f));
     gfx::Transform reflection;
     reflection.Scale3d(-1.0, 1.0, 1.0);
     grand_child1_replica->SetTransform(reflection);
+    grand_child1_replica->SetParent(grand_child1);

[ajuma, 2016/03/30 21:56:05]

Why do tests still need to set the parent of mask and replica layers?

[jaydasika, 2016/03/30 21:59:32]

We don't need parent for masks but need it for replica's as we build property
trees for replicas. (I mean replicas are part of the recursion of building
property trees like other children).

[ajuma, 2016/03/30 22:02:52]

Oh, ok. Do we have other tests that construct replicas on the main thread rather
than on LayerImpl? (Just want to make sure we have test coverage for replica
LayerImpls that aren't children of any layer.)

[jaydasika, 2016/03/30 22:10:08]

There are many tests. One random example :
LayerTreeHostMasksPixelTest.MaskWithReplicaOfClippedLayer

[ajuma, 2016/03/30 23:00:09]

Thanks for checking. Please add a comment here (and in the other tests) that
this is only needed for property tree building.

[jaydasika, 2016/03/30 23:29:46]

Done.

     grand_child1->SetReplicaLayer(std::move(grand_child1_replica));
     grand_child1->SetForceRenderSurface(true);
   }
   LayerImpl* grand_child1_replica = grand_child1->replica_layer();
 
   // Set up the mask layer on the replica layer
   {
     scoped_ptr<LayerImpl> replica_mask_layer =
             LayerImpl::Create(host_impl_.active_tree(), 7);
     replica_mask_layer->SetPosition(gfx::PointF());
@@ skipping 152 matching lines @@
     gfx::Rect root_damage_rect =
         root->render_surface()->damage_tracker()->current_damage_rect();
     gfx::Rect damage_we_care_about = gfx::Rect(i, i);
     EXPECT_LE(damage_we_care_about.right(), root_damage_rect.right());
     EXPECT_LE(damage_we_care_about.bottom(), root_damage_rect.bottom());
   }
 }
 
 }  // namespace
 }  // namespace cc