Add FileSystemHandle::move() method

EXPLAINER.md

@@ -232,12 +232,10 @@ const file_ref = await dir_ref.getFile('foo.js');
 // Get a subdirectory.
 const subdir = await dir_ref.getDirectory('bla', {create: true});
 
-// No special API to create copies, but still possible to do so by using
-// available read and write APIs.
-const new_file = await dir_ref.getFile('new_name', {create: true});
-const new_file_writer = await new_file.createWritable();
-await new_file_writer.write(await file_ref.getFile());
-await new_file_writer.close();
+// Rename a file and/or move it to another directory
+await file_ref.rename('new_name');
+await file_ref.move(other_dir_ref);
+await file_ref.move(dir_ref, 'newer_name');
 
 // Or using streams:
 const copy2 = await dir_ref.getFile('new_name', {create: true});

index.bs

@@ -262,6 +262,9 @@ interface FileSystemHandle {
   readonly attribute FileSystemHandleKind kind;
   readonly attribute USVString name;
 
+  Promise<void> rename(USVString name);
+  Promise<void> move(FileSystemDirectoryHandle parent);
+  Promise<void> move(FileSystemDirectoryHandle parent, USVString name);
   Promise<void> remove(optional FileSystemRemoveOptions options = {});
 
   Promise<boolean> isSameEntry(FileSystemHandle other);
@@ -317,6 +320,64 @@ and return {{FileSystemHandleKind/"directory"}} otherwise.
 The <dfn attribute for=FileSystemHandle>name</dfn> attribute must return the [=entry/name=] of the
 associated [=FileSystemHandle/entry=].
 
+### The {{FileSystemHandle/rename()}} method ### {#api-filesystemhandle-rename}
+
+<div class="note domintro">
+  : await |handle| . {{FileSystemHandle/rename()|rename}}({|new_entry_name|})
+  :: Attempts to atomically rename the entry represented by |handle| to
+     |new_entry_name| in the underlying file system.
+
+     For files or directories with multiple hardlinks or symlinks, the entry
+     which is renamed is the entry corresponding to the path which was used
+     to obtain the handle.
+
+     Attempting to rename a file or directory that does not exist or passing an
+     invalid name will result in a promise rejection.
+
+</div>
+
+<div algorithm>
+The <dfn method for=FileSystemHandle>rename(|new_entry_name|)</dfn> method,
+when invoked, must run these steps:
+
+1. TODO
+
+</div>
+
+
+### The {{FileSystemHandle/move()}} method ### {#api-filesystemhandle-move}
+
+<div class="note domintro">
+  : await |handle| . {{FileSystemHandle/move()|move}}({|destination_directory|})
+  :: Attempts to move the entry represented by |handle| to |destination_directory|,
+     while keeping its existing name.
+
+  : await |handle| . {{FileSystemHandle/move()|move}}({|destination_directory|, |new_entry_name|})
+  :: Attempts to move the entry represented by |handle| to |destination_directory|,
+     as well as renaming to |new_entry_name|.
+
+     If |destination_directory| is on the same underlying filesystem, this move
+     will be atomic. Moves to non-local file systems will are not guaranteed to
+     be atomic and will involve duplicating data.
+
+     For files or directories with multiple hardlinks or
+     symlinks, the entry which is renamed is the entry corresponding to the path
+     which was used to obtain the handle.
+
+     Attempting to move a file or directory that does not exist or passing an
+     invalid name will result in a promise rejection.
+
+</div>
+
+<div algorithm>
+The <dfn method for=FileSystemHandle>move(|destination_directory|, |new_entry_name|)</dfn> method,
+when invoked, must run these steps:
+
+1. TODO
+
+</div>
+
+
 ### The {{FileSystemHandle/remove()}} method ### {#api-filesystemhandle-remove}
 
 <div class="note domintro">