De-flake IndexedDB layout tests.

Per the IndexedDB specification, a versionchange transaction is running
until the open request's transaction member is set to null, which
should happen (synchronously) after the onabort() event handler is
called. Therefore, tests can only assume that a transaction stopped
running after the onabort event handler has occurred.

BUG=657968

Review-Url: https://codereview.chromium.org/2538343002
Cr-Commit-Position: refs/heads/master@{#437974}

third_party/WebKit/LayoutTests/TestExpectations

@@ -1895,8 +1895,6 @@ crbug.com/664873 virtual/mojo-loading/http/tests/xmlhttprequest/small-chunks-res
 
 crbug.com/660295 inspector/elements/elements-panel-restore-selection-when-node-comes-later.html [ Pass Failure ]
 
-crbug.com/657968 storage/indexeddb/idbdatabase-createObjectStore-exception-order.html [ Pass Failure ]
-crbug.com/657968 storage/indexeddb/idbdatabase-deleteObjectStore-exception-order.html [ Pass Failure ]
 crbug.com/667236 fast/forms/select/menulist-appearance-basic.html [ NeedsRebaseline ]
 crbug.com/667236 [ Linux ] fast/forms/select/basic-selects.html [ NeedsRebaseline ]
 crbug.com/667236 [ Linux ] fast/forms/select/select-autofilled.html [ NeedsRebaseline ]

third_party/WebKit/LayoutTests/storage/indexeddb/idbdatabase-createObjectStore-exception-order.html

@@ -11,17 +11,18 @@ indexeddb_test(
   (t, db, req) => {
     db.createObjectStore('s');
 
-    req.transaction.abort();
-    req.onerror = null;
+    req.transaction.onabort = () => {
+      setTimeout(t.step_func(() => {
+        assert_throws(
+          'InvalidStateError', () => { db.createObjectStore('s2'); },
+          '"running an upgrade transaction" check (InvalidStateError) ' +
+          'should precede "not active" check (TransactionInactiveError)');
 
-    setTimeout(t.step_func(() => {
-      assert_throws(
-        'InvalidStateError', () => { db.createObjectStore('s2'); },
-        '"running an upgrade transaction" check (InvalidStateError) ' +
-        'should precede "not active" check (TransactionInactiveError)');
-
-      t.done();
-    }), 0);
+        t.done();
+      }), 0);
+    };
+    req.onerror = null;
+    req.transaction.abort();
   },
   (t, db) => { t.assert_unreached('open should fail'); },
   'IDBDatabase.createObjectStore exception order: ' +
@@ -32,8 +33,8 @@ indexeddb_test(
   (t, db, req) => {
     const store = db.createObjectStore('s');
 
-    req.transaction.abort();
     req.onerror = null;
+    req.transaction.abort();
 
     assert_throws(
       'TransactionInactiveError',

third_party/WebKit/LayoutTests/storage/indexeddb/idbdatabase-deleteObjectStore-exception-order.html

@@ -10,15 +10,17 @@
 indexeddb_test(
   (t, db, req) => {
     db.createObjectStore('s');
-    req.transaction.abort();
+    req.transaction.onabort = () => {
+      setTimeout(t.step_func(() => {
+        assert_throws(
+          'InvalidStateError', () => { db.deleteObjectStore('s'); },
+          '"running an upgrade transaction" check (InvalidStateError) ' +
+          'should precede "not active" check (TransactionInactiveError)');
+        t.done();
+      }), 0);
+    };
     req.onerror = null;
-    setTimeout(t.step_func(() => {
-      assert_throws(
-        'InvalidStateError', () => { db.deleteObjectStore('s'); },
-        '"running an upgrade transaction" check (InvalidStateError) ' +
-        'should precede "not active" check (TransactionInactiveError)');
-      t.done();
-    }), 0);
+    req.transaction.abort();
   },
   (t, db) => { t.assert_unreached('open should fail'); },
   'IDBDatabase.deleteObjectStore exception order: ' +
@@ -27,8 +29,8 @@ indexeddb_test(
 
 indexeddb_test(
   (t, db, req) => {
-    req.transaction.abort();
     req.onerror = null;
+    req.transaction.abort();
     assert_throws(
       'TransactionInactiveError', () => { db.deleteObjectStore('nope'); },
       '"not active" check (TransactionInactiveError) should precede ' +