Fix resourceless software draw

cc/trees/layer_tree_host_common_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/layer_tree_host_common.h"
 
 #include <algorithm>
 #include <set>
 
 #include "cc/animation/layer_animation_controller.h"
@@ skipping 7013 matching lines @@
 
   {
     LayerImplList render_surface_layer_list;
     FakeLayerTreeHostImpl::RecursiveUpdateNumChildren(root.get());
     LayerTreeHostCommon::CalcDrawPropsImplInputsForTesting inputs(
         root.get(), root->bounds(), &render_surface_layer_list);
     inputs.can_render_to_separate_surface = true;
     LayerTreeHostCommon::CalculateDrawProperties(&inputs);
 
     EXPECT_EQ(2u, render_surface_layer_list.size());
+
+    int count_represents_target_render_surface = 0;
+    int count_represents_contributing_render_surface = 0;
+    int count_represents_itself = 0;
+    auto end = LayerIterator<LayerImpl>::End(&render_surface_layer_list);
+    for (auto it = LayerIterator<LayerImpl>::Begin(&render_surface_layer_list);
+         it != end; ++it) {
+      if (it.represents_target_render_surface())
+        count_represents_target_render_surface++;
+      if (it.represents_contributing_render_surface())
+        count_represents_contributing_render_surface++;
+      if (it.represents_itself())
+        count_represents_itself++;
+    }
+
+    // Two render surfaces.
+    EXPECT_EQ(2, count_represents_target_render_surface);
+    // Second render surface contributes to root render surface.
+    EXPECT_EQ(1, count_represents_contributing_render_surface);
+    // All 4 layers represent itself.
+    EXPECT_EQ(4, count_represents_itself);
   }
 
   {
     LayerImplList render_surface_layer_list;
     LayerTreeHostCommon::CalcDrawPropsImplInputsForTesting inputs(
         root.get(), root->bounds(), &render_surface_layer_list);
     inputs.can_render_to_separate_surface = false;
     LayerTreeHostCommon::CalculateDrawProperties(&inputs);
 
     EXPECT_EQ(1u, render_surface_layer_list.size());
+
+    int count_represents_target_render_surface = 0;
+    int count_represents_contributing_render_surface = 0;
+    int count_represents_itself = 0;
+    auto end = LayerIterator<LayerImpl>::End(&render_surface_layer_list);
+    for (auto it = LayerIterator<LayerImpl>::Begin(&render_surface_layer_list);
+         it != end; ++it) {
+      if (it.represents_target_render_surface())
+        count_represents_target_render_surface++;
+      if (it.represents_contributing_render_surface())
+        count_represents_contributing_render_surface++;
+      if (it.represents_itself())
+        count_represents_itself++;
+    }
+
+    // Only root layer has a render surface.
+    EXPECT_EQ(1, count_represents_target_render_surface);
+    // No layer contributes a render surface to root render surface.
+    EXPECT_EQ(0, count_represents_contributing_render_surface);
+    // All 4 layers represent itself.
+    EXPECT_EQ(4, count_represents_itself);
   }
 }
 
 TEST_F(LayerTreeHostCommonTest, DoNotIncludeBackfaceInvisibleSurfaces) {
   scoped_refptr<Layer> root = Layer::Create();
   scoped_refptr<Layer> render_surface = Layer::Create();
   scoped_refptr<LayerWithForcedDrawsContent> child =
       make_scoped_refptr(new LayerWithForcedDrawsContent);
 
   root->AddChild(render_surface);
@@ skipping 1753 matching lines @@
   surface->AddChild(box);
 
   scoped_ptr<FakeLayerTreeHost> host(CreateFakeLayerTreeHost());
   host->SetRootLayer(root);
 
   ExecuteCalculateDrawProperties(root.get());
 }
 
 }  // namespace
 }  // namespace cc