Make ui::LayerOwner::SetLayer a protected method.

The goal is to make it easy to verify that an aura::Window always
has a layer once initialized.

Bug: 738387
Change-Id: I09c4972006c8a4b86fcde0e39fc12291187e0a78
Reviewed-on: https://chromium-review.googlesource.com/774909
Commit-Queue: François Doray <fdoray@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517418}

ui/compositor/layer_owner.h

@@ -19,8 +19,6 @@ class COMPOSITOR_EXPORT LayerOwner {
   LayerOwner();
   virtual ~LayerOwner();
 
-  void SetLayer(std::unique_ptr<Layer> layer);
-
   // Releases the owning reference to its layer, and returns it.
   // This is used when you need to animate the presentation of the owner just
   // prior to destroying it. The Owner can be destroyed soon after calling this
@@ -42,6 +40,7 @@ class COMPOSITOR_EXPORT LayerOwner {
   bool OwnsLayer() const;
 
  protected:
+  void SetLayer(std::unique_ptr<Layer> layer);
   void DestroyLayer();
 
  private:

ui/compositor/layer_owner_unittest.cc

@@ -4,6 +4,8 @@
 
 #include "ui/compositor/layer_owner.h"
 
+#include <utility>
+
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/test/null_task_runner.h"
@@ -41,6 +43,9 @@ class TestLayerAnimationObserver : public ImplicitAnimationObserver {
 
 class LayerOwnerForTesting : public LayerOwner {
  public:
+  LayerOwnerForTesting(std::unique_ptr<Layer> layer) {
+    SetLayer(std::move(layer));
+  }
   void DestroyLayerForTesting() { DestroyLayer(); }
 };
 
@@ -94,8 +99,7 @@ void LayerOwnerTestWithCompositor::TearDown() {
 }  // namespace
 
 TEST_F(LayerOwnerTestWithCompositor, RecreateRootLayerWithCompositor) {
-  LayerOwner owner;
-  owner.SetLayer(std::make_unique<Layer>());
+  LayerOwnerForTesting owner(std::make_unique<Layer>());
   Layer* layer = owner.layer();
   compositor()->SetRootLayer(layer);
 
@@ -110,8 +114,7 @@ TEST_F(LayerOwnerTestWithCompositor, RecreateRootLayerWithCompositor) {
 // properly updates the compositor. So that compositor is not null for observers
 // of animations being cancelled.
 TEST_F(LayerOwnerTestWithCompositor, RecreateRootLayerDuringAnimation) {
-  LayerOwner owner;
-  owner.SetLayer(std::make_unique<Layer>());
+  LayerOwnerForTesting owner(std::make_unique<Layer>());
   Layer* layer = owner.layer();
   compositor()->SetRootLayer(layer);
 
@@ -145,8 +148,7 @@ TEST_F(LayerOwnerTestWithCompositor, RecreateNonRootLayerDuringAnimation) {
   std::unique_ptr<Layer> root_layer(new Layer);
   compositor()->SetRootLayer(root_layer.get());
 
-  LayerOwner owner;
-  owner.SetLayer(std::make_unique<Layer>());
+  LayerOwnerForTesting owner(std::make_unique<Layer>());
   Layer* layer = owner.layer();
   root_layer->Add(layer);
 
@@ -179,8 +181,7 @@ TEST_F(LayerOwnerTestWithCompositor, DetachTimelineOnAnimatorDeletion) {
   std::unique_ptr<Layer> root_layer(new Layer);
   compositor()->SetRootLayer(root_layer.get());
 
-  LayerOwnerForTesting owner;
-  owner.SetLayer(std::make_unique<Layer>());
+  LayerOwnerForTesting owner(std::make_unique<Layer>());
   Layer* layer = owner.layer();
   layer->SetOpacity(0.5f);
   root_layer->Add(layer);
@@ -202,8 +203,7 @@ TEST_F(LayerOwnerTestWithCompositor,
   std::unique_ptr<Layer> root_layer(new Layer);
   compositor()->SetRootLayer(root_layer.get());
 
-  LayerOwner owner;
-  owner.SetLayer(std::make_unique<Layer>());
+  LayerOwnerForTesting owner(std::make_unique<Layer>());
   Layer* layer = owner.layer();
   root_layer->Add(layer);