cc: Pass Occlusion instead of OcclusionTracker to LayerImpls

cc/layers/heads_up_display_layer_impl_unittest.cc

Index: cc/layers/heads_up_display_layer_impl_unittest.cc
diff --git a/cc/layers/heads_up_display_layer_impl_unittest.cc b/cc/layers/heads_up_display_layer_impl_unittest.cc
index 828a93a42bb2649d483384a895cff3754b319c48..c6285314d16663e3e5261eb48716f51985de2587 100644
--- a/cc/layers/heads_up_display_layer_impl_unittest.cc
+++ b/cc/layers/heads_up_display_layer_impl_unittest.cc
@@ -17,12 +17,11 @@ namespace {
 void CheckDrawLayer(HeadsUpDisplayLayerImpl* layer,
                     ResourceProvider* resource_provider,
                     DrawMode draw_mode) {
-  MockOcclusionTracker<LayerImpl> occlusion_tracker;
   scoped_ptr<RenderPass> render_pass = RenderPass::Create();
   AppendQuadsData data;
   bool will_draw = layer->WillDraw(draw_mode, resource_provider);
   if (will_draw)
-    layer->AppendQuads(render_pass.get(), occlusion_tracker, &data);
+    layer->AppendQuads(render_pass.get(), Occlusion(), &data);
   layer->UpdateHudTexture(draw_mode, resource_provider);
   if (will_draw)
     layer->DidDraw(resource_provider);