Make chrome.fileSystem.chooseEntry work on Google Drive directories.

chrome/browser/chromeos/drive/file_system_util.cc

Index: chrome/browser/chromeos/drive/file_system_util.cc
diff --git a/chrome/browser/chromeos/drive/file_system_util.cc b/chrome/browser/chromeos/drive/file_system_util.cc
index d5398712a069e0521466fd013f255d9039d4ddf5..46eb9fae50218c5275cfc664fe92b49c358a2087 100644
--- a/chrome/browser/chromeos/drive/file_system_util.cc
+++ b/chrome/browser/chromeos/drive/file_system_util.cc
@@ -109,6 +109,15 @@ DriveIntegrationService* GetIntegrationServiceByProfile(Profile* profile) {
   return service;
 }
 
+void CheckDirectoryExistsAfterGetResourceEntry(
+    const FileOperationCallback& callback,
+    FileError error,
+    scoped_ptr<ResourceEntry> entry) {
+  if (error == FILE_ERROR_OK && !entry->file_info().is_directory())
+    error = FILE_ERROR_NOT_A_DIRECTORY;
+  callback.Run(error);
+}
+
 }  // namespace
 
 const base::FilePath& GetDriveGrandRootPath() {
@@ -343,6 +352,20 @@ void EnsureDirectoryExists(Profile* profile,
   }
 }
 
+void CheckDirectoryExists(Profile* profile,
+                          const base::FilePath& directory,
+                          const FileOperationCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
+
+  FileSystemInterface* file_system = GetFileSystemByProfile(profile);
+  DCHECK(file_system);
+
+  file_system->GetResourceEntry(
+      ExtractDrivePath(directory),
+      base::Bind(&CheckDirectoryExistsAfterGetResourceEntry, callback));
+}
+
 void EmptyFileOperationCallback(FileError error) {
 }