Move absolute path conversion back to the FILE thread.

chrome/browser/extensions/api/file_system/file_system_api.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/api/file_system/file_system_api.h"
 
 #include <set>
 
 #include "apps/saved_files_service.h"
 #include "base/bind.h"
@@ skipping 621 matching lines @@
     AppWindow* app_window =
         registry->GetAppWindowForRenderViewHost(render_view_host());
     if (!app_window) {
       error_ = kInvalidCallingPage;
       SendResponse(false);
       return;
     }
     content::WebContents* web_contents = app_window->web_contents();
 
     DCHECK_EQ(paths.size(), 1u);
+    bool non_native_path = false;
 #if defined(OS_CHROMEOS)
-    base::FilePath check_path =
-        file_manager::util::IsUnderNonNativeLocalPath(GetProfile(), paths[0])
-            ? paths[0]
-            : base::MakeAbsoluteFilePath(paths[0]);
-#else
-    base::FilePath check_path = base::MakeAbsoluteFilePath(paths[0]);
+    non_native_path =
+        file_manager::util::IsUnderNonNativeLocalPath(GetProfile(), paths[0]);
 #endif
 
     content::BrowserThread::PostTask(
         content::BrowserThread::FILE,
         FROM_HERE,
         base::Bind(
             &FileSystemChooseEntryFunction::ConfirmDirectoryAccessOnFileThread,
             this,
-            check_path,
+            non_native_path,
             paths,
             web_contents));
     return;
   }
 
   OnDirectoryAccessConfirmed(paths);
 }
 
 void FileSystemChooseEntryFunction::FileSelectionCanceled() {
   error_ = kUserCancelled;
   SendResponse(false);
 }
 
 void FileSystemChooseEntryFunction::ConfirmDirectoryAccessOnFileThread(
-    const base::FilePath& check_path,
+    bool non_native_path,
     const std::vector<base::FilePath>& paths,
     content::WebContents* web_contents) {
+  base::FilePath check_path =

[mtomasz, 2015/03/20 01:00:27]

nit: This can be const.

+      non_native_path ? paths[0] : base::MakeAbsoluteFilePath(paths[0]);
   if (check_path.empty()) {
     content::BrowserThread::PostTask(
         content::BrowserThread::UI,
         FROM_HERE,
         base::Bind(&FileSystemChooseEntryFunction::FileSelectionCanceled,
                    this));
     return;
   }
 
   for (size_t i = 0; i < arraysize(kGraylistedPaths); i++) {
@@ skipping 303 matching lines @@
   return false;
 }
 
 bool FileSystemGetObservedEntriesFunction::RunSync() {
   NOTIMPLEMENTED();
   error_ = kUnknownIdError;
   return false;
 }
 
 }  // namespace extensions