Deprecate FileError in FileAPI

LayoutTests/fast/filesystem/resources/file-writer-abort.js

 if (this.importScripts) {
     importScripts('fs-worker-common.js');
     importScripts('../../js/resources/js-test-pre.js');
     importScripts('file-writer-utils.js');
 }
 
 description("Test that FileWriter handles abort properly.");
 
 var sawWriteStart;
 var sawAbort;
@@ skipping 20 matching lines @@
     writer.abort();
 }
 
 // We should always abort before completion.
 function onWrite(e) {
     testFailed("In onWrite.");
 }
 
 function onAbort(e) {
     assert(writer.readyState == writer.DONE);
-    assert(writer.error.code == writer.error.ABORT_ERR);
+    assert(writer.error.name == "AbortError");
     assert(sawWriteStart);
     assert(!sawWriteEnd);
     assert(!sawAbort);
     assert(e.type == "abort");
     sawAbort = true;
     testPassed("Saw abort");
 }
 
 function onWriteEnd(e) {
     assert(writer.readyState == writer.DONE);
-    assert(writer.error.code == writer.error.ABORT_ERR);
+    assert(writer.error.name == "AbortError");
     assert(sawWriteStart);
     assert(sawAbort);
     assert(!sawWriteEnd);
     assert(e.type == "writeend");
     sawWriteEnd = true;
     testPassed("Saw writeend.");
     writer.abort();  // Verify that this does nothing in readyState DONE.
     cleanUp();
 }
 
@@ skipping 12 matching lines @@
     fileWriter.onwriteend = onWriteEnd;
     fileWriter.abort();  // Verify that this does nothing in readyState INIT.
     fileWriter.write(blob);
 }
 
 function runTest(unusedFileEntry, fileWriter) {
     startWrite(fileWriter);
 }
 var jsTestIsAsync = true;
 setupAndRunTest(2*1024*1024, 'file-writer-abort', runTest);