Add FileSystemMountPointProvider::CreateFileReader() which returns appropriate Reader instance

webkit/fileapi/isolated_mount_point_provider.cc

Index: webkit/fileapi/isolated_mount_point_provider.cc
diff --git a/webkit/fileapi/isolated_mount_point_provider.cc b/webkit/fileapi/isolated_mount_point_provider.cc
index 4e92df2fdff48a21e2543613f7c59c62a4ad3279..02bf8ae8cbdb1d799e240893eb8540233f1ea5a6 100644
--- a/webkit/fileapi/isolated_mount_point_provider.cc
+++ b/webkit/fileapi/isolated_mount_point_provider.cc
@@ -11,9 +11,12 @@
 #include "base/logging.h"
 #include "base/message_loop_proxy.h"
 #include "googleurl/src/gurl.h"
+#include "webkit/blob/local_file_reader.h"
 #include "webkit/fileapi/file_system_callback_dispatcher.h"
+#include "webkit/fileapi/file_system_file_reader.h"
 #include "webkit/fileapi/file_system_operation.h"
 #include "webkit/fileapi/file_system_types.h"
+#include "webkit/fileapi/file_system_util.h"
 #include "webkit/fileapi/isolated_context.h"
 #include "webkit/fileapi/isolated_file_util.h"
 #include "webkit/fileapi/native_file_util.h"
@@ -97,6 +100,26 @@ IsolatedMountPointProvider::CreateFileSystemOperation(
   return new FileSystemOperation(file_proxy, context);
 }
 
+webkit_blob::FileReader* IsolatedMountPointProvider::CreateFileReader(
+    const GURL& url,
+    int64 offset,
+    base::MessageLoopProxy* file_proxy,
+    FileSystemContext* context) const {
+  GURL origin_url;
+  FileSystemType file_system_type = kFileSystemTypeUnknown;
+  FilePath virtual_path;
+  if (!CrackFileSystemURL(url, &origin_url, &file_system_type, &virtual_path))
+    return NULL;
+  std::string fsid;
+  FilePath path;
+  if (!isolated_context()->CrackIsolatedPath(virtual_path, &fsid, NULL, &path))
+    return NULL;
+  if (path.empty())
+    return NULL;
+  return new webkit_blob::LocalFileReader(
+      file_proxy, path, offset, base::Time());
+}
+
 IsolatedContext* IsolatedMountPointProvider::isolated_context() const {
   return IsolatedContext::GetInstance();
 }