FileAPI: Add Initialize() function to FileSystemBackend

chrome/browser/media_galleries/fileapi/media_file_system_backend.cc

Index: chrome/browser/media_galleries/fileapi/media_file_system_backend.cc
diff --git a/chrome/browser/media_galleries/fileapi/media_file_system_backend.cc b/chrome/browser/media_galleries/fileapi/media_file_system_backend.cc
index 308b252936d5da8575a13e75aac69093c8530fb1..59809bb04fbb766226b1428c1f33583ca4885c25 100644
--- a/chrome/browser/media_galleries/fileapi/media_file_system_backend.cc
+++ b/chrome/browser/media_galleries/fileapi/media_file_system_backend.cc
@@ -103,12 +103,14 @@ bool MediaFileSystemBackend::CanHandleType(
   }
 }
 
-void MediaFileSystemBackend::InitializeFileSystem(
+void MediaFileSystemBackend::Initialize(fileapi::FileSystemContext* context) {
+}
+
+void MediaFileSystemBackend::OpenFileSystem(
     const GURL& origin_url,
     fileapi::FileSystemType type,
     fileapi::OpenFileSystemMode mode,
-    fileapi::FileSystemContext* context,
-    const InitializeFileSystemCallback& callback) {
+    const OpenFileSystemCallback& callback) {
   // We never allow opening a new isolated FileSystem via usual OpenFileSystem.
   base::MessageLoopProxy::current()->PostTask(
       FROM_HERE,