Removing the assumption that child->SetParent will not change Drawability

cc/layers/layer_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/layers/layer.h"
 
 #include "cc/animation/keyframed_animation_curve.h"
 #include "cc/base/math_util.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/resources/layer_painter.h"
@@ skipping 38 matching lines @@
   MOCK_METHOD0(SetNeedsFullTreeSync, void());
 };
 
 class MockLayerPainter : public LayerPainter {
  public:
   virtual void Paint(SkCanvas* canvas,
                      const gfx::Rect& content_rect,
                      gfx::RectF* opaque) OVERRIDE {}
 };
 
-
 class LayerTest : public testing::Test {
  public:
   LayerTest()
       : host_impl_(&proxy_, &shared_bitmap_manager_),
         fake_client_(FakeLayerTreeHostClient::DIRECT_3D) {}
 
  protected:
   virtual void SetUp() OVERRIDE {
     layer_tree_host_.reset(new StrictMock<MockLayerTreeHost>(&fake_client_));
   }
@@ skipping 1075 matching lines @@
         } else {
           EXPECT_NE(SkColorGetA(safe_color), 255u)
               << "Flags: " << contents_opaque << ", " << layer_opaque << ", "
               << host_opaque << "\n";
         }
       }
     }
   }
 }
 
+class DrawsContentChangeLayer : public Layer {
+ public:
+  static scoped_refptr<DrawsContentChangeLayer> Create() {
+    return make_scoped_refptr(new DrawsContentChangeLayer());
+  }
+
+  virtual void SetLayerTreeHost(LayerTreeHost* host) OVERRIDE {
+    Layer::SetLayerTreeHost(host);
+    SetFakeDrawsContent(!fake_draws_content_);
+  }
+
+  virtual bool HasDrawableContent() const OVERRIDE {
+    return fake_draws_content_ && Layer::HasDrawableContent();
+  }
+
+  void SetFakeDrawsContent(bool fake_draws_content) {
+    fake_draws_content_ = fake_draws_content;
+    UpdateDrawsContent(HasDrawableContent());
+  }
+
+ private:
+  DrawsContentChangeLayer() : Layer(), fake_draws_content_(false) {}
+  virtual ~DrawsContentChangeLayer() OVERRIDE {}
+
+  bool fake_draws_content_;
+};
+
+TEST_F(LayerTest, DrawsContentChangedInSetLayerTreeHost) {
+  scoped_refptr<Layer> root_layer = Layer::Create();
+  scoped_refptr<DrawsContentChangeLayer> becomes_not_draws_content =
+      DrawsContentChangeLayer::Create();
+  scoped_refptr<DrawsContentChangeLayer> becomes_draws_content =
+      DrawsContentChangeLayer::Create();
+  root_layer->SetIsDrawable(true);
+  becomes_not_draws_content->SetIsDrawable(true);
+  becomes_not_draws_content->SetFakeDrawsContent(true);
+  EXPECT_EQ(0, root_layer->NumDescendantsThatDrawContent());
+  root_layer->AddChild(becomes_not_draws_content);
+  EXPECT_EQ(0, root_layer->NumDescendantsThatDrawContent());
+
+  becomes_draws_content->SetIsDrawable(true);
+  root_layer->AddChild(becomes_draws_content);
+  EXPECT_EQ(1, root_layer->NumDescendantsThatDrawContent());
+}
+
 }  // namespace
 }  // namespace cc