Replace mountType by volumeType on fileBrowserPrivate APIs.

chrome/browser/chromeos/extensions/file_manager/private_api_util.h

Index: chrome/browser/chromeos/extensions/file_manager/private_api_util.h
diff --git a/chrome/browser/chromeos/extensions/file_manager/private_api_util.h b/chrome/browser/chromeos/extensions/file_manager/private_api_util.h
index be2e15e0482b4b86a2d6cd6e2bc483775667beed..18ff3a9b245a13f09da61ef6e546090550dc56eb 100644
--- a/chrome/browser/chromeos/extensions/file_manager/private_api_util.h
+++ b/chrome/browser/chromeos/extensions/file_manager/private_api_util.h
@@ -8,6 +8,7 @@
 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_MANAGER_PRIVATE_API_UTIL_H_
 
 #include "base/callback_forward.h"
+#include "chrome/browser/chromeos/extensions/file_manager/volume_manager.h"
 #include "chrome/browser/google_apis/gdata_wapi_parser.h"
 #include "url/gurl.h"
 
@@ -25,6 +26,9 @@ struct SelectedFileInfo;
 namespace file_manager {
 namespace util {
 
+// Converts VolumeType to a string enum (volumeType) used in the private API.
+std::string VolumeTypeToStringEnum(VolumeType type);
+
 // Returns the ID of the tab associated with the dispatcher. Returns 0 on
 // error.
 int32 GetTabId(ExtensionFunctionDispatcher* dispatcher);