mediaview: Add a typemap for arc::mojom::ChangeType.

components/arc/test/fake_file_system_instance.cc

Index: components/arc/test/fake_file_system_instance.cc
diff --git a/components/arc/test/fake_file_system_instance.cc b/components/arc/test/fake_file_system_instance.cc
index 4a3dcc89b826e8c5f6722049b094f378c8af7b23..f522024e2c1f847d018479fc0045790146709617 100644
--- a/components/arc/test/fake_file_system_instance.cc
+++ b/components/arc/test/fake_file_system_instance.cc
@@ -121,9 +121,10 @@ void FakeFileSystemInstance::AddDocument(const Document& document) {
   }
 }
 
-void FakeFileSystemInstance::TriggerWatchers(const std::string& authority,
-                                             const std::string& document_id,
-                                             mojom::ChangeType type) {
+void FakeFileSystemInstance::TriggerWatchers(
+    const std::string& authority,
+    const std::string& document_id,
+    storage::WatcherManager::ChangeType type) {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (!host_) {
     LOG(ERROR) << "FileSystemHost is not available.";