Add support for persistent file access in apps.

chrome/renderer/extensions/file_system_natives.cc

Index: chrome/renderer/extensions/file_system_natives.cc
diff --git a/chrome/renderer/extensions/file_system_natives.cc b/chrome/renderer/extensions/file_system_natives.cc
index fd356e495760f66c2c5f5f7192733dfdd490ae8a..984c7bf79cc5b83ccf6bf209904cab1ddcf5a12e 100644
--- a/chrome/renderer/extensions/file_system_natives.cc
+++ b/chrome/renderer/extensions/file_system_natives.cc
@@ -28,6 +28,9 @@ FileSystemNatives::FileSystemNatives(v8::Handle<v8::Context> context)
   RouteFunction("GetIsolatedFileSystem",
       base::Bind(&FileSystemNatives::GetIsolatedFileSystem,
                  base::Unretained(this)));
+  RouteFunction("CrackIsolatedFileSystemName",
+      base::Bind(&FileSystemNatives::CrackIsolatedFileSystemName,
+                 base::Unretained(this)));
 }
 
 v8::Handle<v8::Value> FileSystemNatives::GetIsolatedFileSystem(
@@ -98,4 +101,16 @@ v8::Handle<v8::Value> FileSystemNatives::GetFileEntry(
       is_directory);
 }
 
+v8::Handle<v8::Value> FileSystemNatives::CrackIsolatedFileSystemName(
+    const v8::Arguments& args) {
+  DCHECK_EQ(args.Length(), 1);
+  DCHECK(args[0]->IsString());
+  std::string filesystem_name = *v8::String::Utf8Value(args[0]->ToString());
+  std::string filesystem_id;
+  if (!fileapi::CrackIsolatedFileSystemName(filesystem_name, &filesystem_id))
+    return v8::Undefined();
+
+  return v8::String::New(filesystem_id.c_str(), filesystem_id.size());
+}
+
 }  // namespace extensions