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

cc/test/layer_tree_pixel_test.cc

Index: cc/test/layer_tree_pixel_test.cc
diff --git a/cc/test/layer_tree_pixel_test.cc b/cc/test/layer_tree_pixel_test.cc
index ed14e33f0e031fe3649f8176083503a1ff46907f..4e4e0394021a6c7b74927d72feb73afe32e50879 100644
--- a/cc/test/layer_tree_pixel_test.cc
+++ b/cc/test/layer_tree_pixel_test.cc
@@ -47,7 +47,8 @@
       software_output_device->set_surface_expansion_size(
           surface_expansion_size);
       output_surface = make_scoped_ptr(
-          new PixelTestOutputSurface(software_output_device.Pass()));
+          new PixelTestOutputSurface(
+              software_output_device.PassAs<SoftwareOutputDevice>()));
       break;
     }
 
@@ -60,7 +61,7 @@
   }
 
   output_surface->set_surface_expansion_size(surface_expansion_size);
-  return output_surface.Pass();
+  return output_surface.PassAs<OutputSurface>();
 }
 
 void LayerTreePixelTest::CommitCompleteOnThread(LayerTreeHostImpl* impl) {
@@ -228,7 +229,7 @@
     const TextureMailbox& texture_mailbox) {
   DCHECK(texture_mailbox.IsTexture());
   if (!texture_mailbox.IsTexture())
-    return nullptr;
+    return scoped_ptr<SkBitmap>();
 
   scoped_ptr<gpu::GLInProcessContext> context = CreateTestInProcessContext();
   GLES2Interface* gl = context->GetImplementation();