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

cc/layers/tiled_layer_unittest.cc

Index: cc/layers/tiled_layer_unittest.cc
diff --git a/cc/layers/tiled_layer_unittest.cc b/cc/layers/tiled_layer_unittest.cc
index d2bc0a986f8141c2cefa904fa9816cd36f0d9f50..e46d66b74ebd3e7b2d5bb7cd2b4edd1f6b690f5e 100644
--- a/cc/layers/tiled_layer_unittest.cc
+++ b/cc/layers/tiled_layer_unittest.cc
@@ -140,8 +140,8 @@
 
     DebugScopedSetImplThreadAndMainThreadBlocked
     impl_thread_and_main_thread_blocked(proxy_);
-    resource_provider_ = nullptr;
-    host_impl_ = nullptr;
+    resource_provider_.reset();
+    host_impl_.reset();
   }
 
   void ResourceManagerClearAllMemory(
@@ -1665,8 +1665,10 @@
       : FakeTiledLayer(manager) {
     scoped_ptr<TrackingLayerPainter> painter(TrackingLayerPainter::Create());
     tracking_layer_painter_ = painter.get();
-    layer_updater_ = BitmapContentLayerUpdater::Create(
-        painter.Pass(), &stats_instrumentation_, 0);
+    layer_updater_ =
+        BitmapContentLayerUpdater::Create(painter.PassAs<LayerPainter>(),
+                                          &stats_instrumentation_,
+                                          0);
   }
 
   TrackingLayerPainter* tracking_layer_painter() const {