Add DeleteRecursively to AsyncFileUtil.

On Drive file system, recursive deletion can be done more efficiently than
removing each file/directory. To support it, this CL adds an optional method
DeleteRecursively to AsyncFileUtil, and use it (if possible) in
LocalFileSystemOperation.
This is the preparation of merging {Remote,Local}FileSystemOperation. Currently
the new method is not used on any platforms, but will be used by Drive File
System.

BUG=110121
TEST=Ran unit_tests

Review URL: https://chromiumcodereview.appspot.com/18314002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@209484 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 20 insertions, 0 deletions

diff --git a/webkit/browser/fileapi/async_file_util.h b/webkit/browser/fileapi/async_file_util.h
index 922bbfc..141d8cf 100644
--- a/webkit/browser/fileapi/async_file_util.h
+++ b/webkit/browser/fileapi/async_file_util.h
@@ -296,6 +296,26 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
       const FileSystemURL& url,
       const StatusCallback& callback) = 0;
 
+  // Removes a single file or a single directory with its contents
+  // (i.e. files/subdirectories under the directory).
+  //
+  // LocalFileSystemOperation::Remove calls this.
+  // On some platforms, such as Chrome OS Drive File System, recursive file
+  // deletion can be implemented more efficiently than calling DeleteFile() and
+  // DeleteDirectory() for each files/directories.
+  // This method is optional, so if not supported,
+  // PLATFORM_ERROR_INVALID_OPERATION should be returned via |callback|.
+  //
+  // This returns false if it fails to post an async task.
+  //
+  // This reports following error code via |callback|:
+  // - PLATFORM_FILE_ERROR_NOT_FOUND if |url| does not exist.
+  // - PLATFORM_ERROR_INVALID_OPERATION if this operation is not supported.
+  virtual bool DeleteRecursively(
+      scoped_ptr<FileSystemOperationContext> context,
+      const FileSystemURL& url,
+      const StatusCallback& callback) = 0;
+
   // Creates a local snapshot file for a given |url| and returns the
   // metadata and platform path of the snapshot file via |callback|.
   // In regular filesystem cases the implementation may simply return