[fsp] Add support for copying files within a provided file system.

chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc

Index: chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc
diff --git a/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc b/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc
index 700340574307fe778a9754c31b0a0aec7782b331..897f18e34fc73b185c0a4d4a856269ac1d7e8cfb 100644
--- a/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc
+++ b/chrome/browser/chromeos/file_system_provider/fake_provided_file_system.cc
@@ -255,6 +255,14 @@ void FakeProvidedFileSystem::CreateFile(
                                               base::Bind(callback, result));
 }
 
+void FakeProvidedFileSystem::CopyEntry(
+    const base::FilePath& source_path,
+    const base::FilePath& target_path,
+    const fileapi::AsyncFileUtil::StatusCallback& callback) {
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE, base::Bind(callback, base::File::FILE_OK));
+}
+
 const ProvidedFileSystemInfo& FakeProvidedFileSystem::GetFileSystemInfo()
     const {
   return file_system_info_;