mojo: Use stl utilities from the base namespace

mojo/public/cpp/bindings/lib/sync_handle_registry.cc

Index: mojo/public/cpp/bindings/lib/sync_handle_registry.cc
diff --git a/mojo/public/cpp/bindings/lib/sync_handle_registry.cc b/mojo/public/cpp/bindings/lib/sync_handle_registry.cc
index f6372d9eb51d6ecb0df89807b8abc045a90587c9..ef236953404b92873a3812f701a51171a822e9da 100644
--- a/mojo/public/cpp/bindings/lib/sync_handle_registry.cc
+++ b/mojo/public/cpp/bindings/lib/sync_handle_registry.cc
@@ -34,7 +34,7 @@ bool SyncHandleRegistry::RegisterHandle(const Handle& handle,
                                         const HandleCallback& callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  if (ContainsKey(handles_, handle))
+  if (base::ContainsKey(handles_, handle))
     return false;
 
   MojoResult result = MojoAddHandle(wait_set_handle_.get().value(),
@@ -48,7 +48,7 @@ bool SyncHandleRegistry::RegisterHandle(const Handle& handle,
 
 void SyncHandleRegistry::UnregisterHandle(const Handle& handle) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  if (!ContainsKey(handles_, handle))
+  if (!base::ContainsKey(handles_, handle))
     return;
 
   MojoResult result =