style: made container APIs more consistent.

Change-Id: Ib4feedfc4c9fb497dfcd67e7e6a33ee03db58d7f
refs: #4337
diff --git a/src/adjacency-list.cpp b/src/adjacency-list.cpp
index eead545..4ceaa82 100644
--- a/src/adjacency-list.cpp
+++ b/src/adjacency-list.cpp
@@ -87,7 +87,7 @@
 bool
 AdjacencyList::operator==(AdjacencyList& adl) const
 {
-  if (m_adjList.size() != adl.getSize()) {
+  if (size() != adl.size()) {
     return false;
   }