Revert of Always create top controls manager

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index d893b33c3374787a4dd4c8ff18e61bf0dce27e8c..92e9c2593fc2a2c8a23eb897d85f37a08b143c33 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -448,8 +448,11 @@
   host_impl->SetUseGpuRasterization(UseGpuRasterization());
   shared_bitmap_manager_ = NULL;
   gpu_memory_buffer_manager_ = NULL;
-  top_controls_manager_weak_ptr_ =
-      host_impl->top_controls_manager()->AsWeakPtr();
+  if (settings_.calculate_top_controls_position &&
+      host_impl->top_controls_manager()) {
+    top_controls_manager_weak_ptr_ =
+        host_impl->top_controls_manager()->AsWeakPtr();
+  }
   input_handler_weak_ptr_ = host_impl->AsWeakPtr();
   return host_impl.Pass();
 }
@@ -1155,6 +1158,9 @@
 void LayerTreeHost::UpdateTopControlsState(TopControlsState constraints,
                                            TopControlsState current,
                                            bool animate) {
+  if (!settings_.calculate_top_controls_position)
+    return;
+
   // Top controls are only used in threaded mode.
   proxy_->ImplThreadTaskRunner()->PostTask(
       FROM_HERE,