Cleans up usage of ViewManagerServiceImpl::roots_

mojo/services/view_manager/ids.h

Index: mojo/services/view_manager/ids.h
diff --git a/mojo/services/view_manager/ids.h b/mojo/services/view_manager/ids.h
index 593497f231c867cc41d3bca6f13b1432e3b2bb02..71e38332a3482a6d3c1c041615dac16e73cdcfe8 100644
--- a/mojo/services/view_manager/ids.h
+++ b/mojo/services/view_manager/ids.h
@@ -12,8 +12,9 @@
 namespace mojo {
 namespace service {
 
-// Connection id reserved for the root.
-const ConnectionSpecificId kRootConnection = 0;
+// Connection id is used to indicate no connection. That is, no
+// ViewManagerServiceImpl ever gets this id.
+const ConnectionSpecificId kInvalidConnectionId = 0;
 
 // TODO(sky): remove this, temporary while window manager API is in existing
 // api.
@@ -77,13 +78,13 @@ inline Id ViewIdToTransportId(const ViewId& id) {
 }
 
 inline NodeId RootNodeId() {
-  return NodeId(kRootConnection, 1);
+  return NodeId(kInvalidConnectionId, 1);
 }
 
 // Returns a NodeId that is reserved to indicate no node. That is, no node will
 // ever be created with this id.
 inline NodeId InvalidNodeId() {
-  return NodeId(kRootConnection, 0);
+  return NodeId(kInvalidConnectionId, 0);
 }
 
 }  // namespace service