Add delegate and factory function for ChildMemoryCoordinator

components/memory_coordinator/child/child_memory_coordinator_impl.cc

Index: components/memory_coordinator/child/child_memory_coordinator_impl.cc
diff --git a/components/memory_coordinator/child/child_memory_coordinator_impl.cc b/components/memory_coordinator/child/child_memory_coordinator_impl.cc
index 8251827635868ca99a4b64fda8da72ec1ec3fecf..1e4a9c8ecd22df7664935112f75398660279c1ba 100644
--- a/components/memory_coordinator/child/child_memory_coordinator_impl.cc
+++ b/components/memory_coordinator/child/child_memory_coordinator_impl.cc
@@ -7,8 +7,10 @@
 namespace memory_coordinator {
 
 ChildMemoryCoordinatorImpl::ChildMemoryCoordinatorImpl(
-    mojom::MemoryCoordinatorHandlePtr parent)
-    : binding_(this), parent_(std::move(parent)) {
+    mojom::MemoryCoordinatorHandlePtr parent,
+    ChildMemoryCoordinatorDelegate* delegate)
+    : binding_(this), parent_(std::move(parent)), delegate_(delegate) {
+  DCHECK(delegate_);
   parent_->AddChild(binding_.CreateInterfacePtrAndBind());
 }
 
@@ -20,4 +22,13 @@ void ChildMemoryCoordinatorImpl::OnStateChange(mojom::MemoryState state) {
                     state);
 }
 
+#if !defined(OS_ANDROID)
+std::unique_ptr<ChildMemoryCoordinatorImpl> CreateChildMemoryCoordinator(
+    mojom::MemoryCoordinatorHandlePtr parent,
+    ChildMemoryCoordinatorDelegate* delegate) {
+  return base::WrapUnique(
+      new ChildMemoryCoordinatorImpl(std::move(parent), delegate));
+}
+#endif
+
 }  // namespace memory_coordinator