drive: Stop using callback for ResourceMetadataStorage::Iterate

chrome/browser/chromeos/drive/resource_metadata.h

Index: chrome/browser/chromeos/drive/resource_metadata.h
diff --git a/chrome/browser/chromeos/drive/resource_metadata.h b/chrome/browser/chromeos/drive/resource_metadata.h
index 3a87c0e4515e0ef181820b7f211607fce6d33cf6..054dbf517f3dce636af608b0d7004b248225548a 100644
--- a/chrome/browser/chromeos/drive/resource_metadata.h
+++ b/chrome/browser/chromeos/drive/resource_metadata.h
@@ -16,7 +16,6 @@
 #include "base/memory/weak_ptr.h"
 #include "base/time.h"
 #include "chrome/browser/chromeos/drive/file_errors.h"
-#include "chrome/browser/chromeos/drive/resource_metadata_storage.h"
 
 namespace base {
 class SequencedTaskRunner;
@@ -117,6 +116,8 @@ struct EntryInfoPairResult {
 typedef base::Callback<void(scoped_ptr<EntryInfoPairResult> pair_result)>
     GetEntryInfoPairCallback;
 
+typedef base::Callback<void(const ResourceEntry& entry)> IterateCallback;
+
 namespace internal {
 
 // Storage for Drive Metadata.