[NativeFS] Update permissions API following spec change.

This implements the changes from WICG/file-system-access#201.

Change-Id: I9702f9888c4f0fff2084143ac6077b8484dfce16

native-file-system/resources/messaging-serialize-helpers.js

@@ -31,10 +31,10 @@ async function serialize_handle(handle) {
 // FileSystemDirectoryHandle.
 async function serialize_file_system_handle(handle) {
   const read_permission =
-    await handle.queryPermission({ writable: false });
+    await handle.queryPermission({ mode: 'read' });
 
   const write_permission =
-    await handle.queryPermission({ writable: true })
+    await handle.queryPermission({ mode: 'readwrite' })
 
   return {
     kind: handle.kind,

native-file-system/resources/native-fs-test-helpers.js

@@ -41,14 +41,14 @@ function directory_test(func, description) {
 }
 
 directory_test(async (t, dir) => {
-  assert_equals(await dir.queryPermission({writable: false}), 'granted');
+  assert_equals(await dir.queryPermission({mode: 'read'}), 'granted');
 }, 'User succesfully selected an empty directory.');
 
 directory_test(async (t, dir) => {
-  const status = await dir.queryPermission({writable: true});
+  const status = await dir.queryPermission({mode: 'readwrite'});
   if (status == 'granted')
     return;
 
   await window.test_driver.bless('ask for write permission');
-  assert_equals(await dir.requestPermission({writable: true}), 'granted');
+  assert_equals(await dir.requestPermission({mode: 'readwrite'}), 'granted');
 }, 'User granted write access.');

native-file-system/showSaveFilePicker-manual.https.html

@@ -26,7 +26,7 @@
 
     promise_test(async t => {
       assert_equals(await file.queryPermission(), 'granted');
-      assert_equals(await file.queryPermission({ writable: true }), 'granted');
+      assert_equals(await file.queryPermission({ mode: 'readwrite' }), 'granted');
     }, 'showSaveFilePicker returns correct permissions');
   }, 'showSaveFilePicker works');