[SyncFS] Make DumpFiles async

chrome/browser/sync_file_system/sync_file_system_service.cc

Index: chrome/browser/sync_file_system/sync_file_system_service.cc
diff --git a/chrome/browser/sync_file_system/sync_file_system_service.cc b/chrome/browser/sync_file_system/sync_file_system_service.cc
index 9f19c7e7a415bf882bbf793ae13024a68d977825..2811457ce12c546e76d2183e12f8efc0f0f65457 100644
--- a/chrome/browser/sync_file_system/sync_file_system_service.cc
+++ b/chrome/browser/sync_file_system/sync_file_system_service.cc
@@ -132,7 +132,7 @@ void DidGetFileSyncStatusForDump(
   if (++*num_results < files->GetSize())
     return;
 
-  callback.Run(files);
+  callback.Run(*files);
 }
 
 // We need this indirection because WeakPtr can only be bound to methods
@@ -508,28 +508,36 @@ void SyncFileSystemService::DidInitializeFileSystemForDump(
   DCHECK(!origin.is_empty());
 
   if (status != SYNC_STATUS_OK) {
-    base::ListValue empty_result;
-    callback.Run(&empty_result);
+    callback.Run(base::ListValue());
     return;
   }
 
-  base::ListValue* files =
-      GetRemoteService(origin)->DumpFiles(origin).release();
-  if (!files) {
-    callback.Run(new base::ListValue);
-    return;
-  }
+  GetRemoteService(origin)->DumpFiles(
+      origin,
+      base::Bind(
+          &SyncFileSystemService::DidDumpFiles,
+          AsWeakPtr(),
+          origin,
+          callback));
+}
 
-  if (!files->GetSize()) {
-    callback.Run(files);
+void SyncFileSystemService::DidDumpFiles(
+    const GURL& origin,
+    const DumpFilesCallback& callback,
+    scoped_ptr<base::ListValue> dump_files) {
+  if (!dump_files || !dump_files->GetSize()) {
+    callback.Run(base::ListValue());
     return;
   }
 
-  base::Callback<void(base::DictionaryValue* file,
-                      SyncStatusCode sync_status,
-                      SyncFileStatus sync_file_status)> completion_callback =
-      base::Bind(&DidGetFileSyncStatusForDump, base::Owned(files),
-                 base::Owned(new size_t(0)), callback);
+  base::ListValue* files = dump_files.get();
+  base::Callback<void(base::DictionaryValue*,
+                      SyncStatusCode,
+                      SyncFileStatus)> completion_callback =
+      base::Bind(&DidGetFileSyncStatusForDump,
+                 base::Owned(dump_files.release()),
+                 base::Owned(new size_t(0)),
+                 callback);
 
   // After all metadata loaded, sync status can be added to each entry.
   for (size_t i = 0; i < files->GetSize(); ++i) {