Revert of cc: Remove use of PassAs() and constructor-casting with scoped_ptr.

cc/trees/layer_tree_impl_unittest.cc

Index: cc/trees/layer_tree_impl_unittest.cc
diff --git a/cc/trees/layer_tree_impl_unittest.cc b/cc/trees/layer_tree_impl_unittest.cc
index 7fc16457f49fddc862d8596f7a7be30a581cd2f6..a0dd11a266eada46c256831cf66693453ff6b633 100644
--- a/cc/trees/layer_tree_impl_unittest.cc
+++ b/cc/trees/layer_tree_impl_unittest.cc
@@ -25,7 +25,8 @@
     settings.layer_transforms_should_scale_layer_contents = true;
     host_impl_.reset(
         new FakeLayerTreeHostImpl(settings, &proxy_, &shared_bitmap_manager_));
-    EXPECT_TRUE(host_impl_->InitializeRenderer(FakeOutputSurface::Create3d()));
+    EXPECT_TRUE(host_impl_->InitializeRenderer(
+        FakeOutputSurface::Create3d().PassAs<OutputSurface>()));
   }
 
   FakeLayerTreeHostImpl& host_impl() { return *host_impl_; }
@@ -123,7 +124,7 @@
   hud->SetDrawsContent(true);
 
   host_impl().active_tree()->set_hud_layer(hud.get());
-  root->AddChild(hud.Pass());
+  root->AddChild(hud.PassAs<LayerImpl>());
 
   host_impl().SetViewportSize(hud_bounds);
   host_impl().active_tree()->SetRootLayer(root.Pass());