Replace more ObserverList with base::ObserverList.

sync/sessions/directory_type_debug_info_emitter.cc

Index: sync/sessions/directory_type_debug_info_emitter.cc
diff --git a/sync/sessions/directory_type_debug_info_emitter.cc b/sync/sessions/directory_type_debug_info_emitter.cc
index c8228d23a4e85ff928eb48b3c2aa7c9153b68b1c..e1a89e8619b90b45d012cbcfafcc2c9e4af0945e 100644
--- a/sync/sessions/directory_type_debug_info_emitter.cc
+++ b/sync/sessions/directory_type_debug_info_emitter.cc
@@ -14,17 +14,17 @@ namespace syncer {
 DirectoryTypeDebugInfoEmitter::DirectoryTypeDebugInfoEmitter(
     syncable::Directory* directory,
     syncer::ModelType type,
-    ObserverList<TypeDebugInfoObserver>* observers)
+    base::ObserverList<TypeDebugInfoObserver>* observers)
     : directory_(directory),
       type_(type),
-      type_debug_info_observers_(observers) {}
+      type_debug_info_observers_(observers) {
+}
 
 DirectoryTypeDebugInfoEmitter::DirectoryTypeDebugInfoEmitter(
     ModelType type,
-    ObserverList<TypeDebugInfoObserver>* observers)
-    : directory_(NULL),
-      type_(type),
-      type_debug_info_observers_(observers) {}
+    base::ObserverList<TypeDebugInfoObserver>* observers)
+    : directory_(NULL), type_(type), type_debug_info_observers_(observers) {
+}
 
 DirectoryTypeDebugInfoEmitter::~DirectoryTypeDebugInfoEmitter() {}