Move persistent gesture state to Document, add DocumentUserGestureToken

third_party/WebKit/Source/core/dom/DocumentUserGestureToken.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef DocumentUserGestureToken_h
+#define DocumentUserGestureToken_h
+
+#include "core/dom/Document.h"
+#include "platform/UserGestureIndicator.h"
+
+namespace blink {
+
+// Associates a UserGestureToken with a Document, if a non-null Document*
+// is provided in the constructor.
+class DocumentUserGestureToken final : public UserGestureToken {
+  WTF_MAKE_NONCOPYABLE(DocumentUserGestureToken);
+
+ public:
+  static PassRefPtr<UserGestureToken> create(
+      Document* document,
+      Status status = PossiblyExistingGesture) {
+    return adoptRef(new DocumentUserGestureToken(document, status));
+  }
+
+  ~DocumentUserGestureToken() final {}
+
+ private:
+  DocumentUserGestureToken(Document* document, Status status)
+      : UserGestureToken(status) {
+    for (; document; document = document->parentDocument()) {

[Rick Byers, 2016/10/24 18:30:47]

Any thoughts about what should be done for OOPIF?  Perhaps just file a bug for
now (cc'ing some site-isolation-dev folks like kenrb) and reference it with a
TODO here?

[Nate Chapin, 2016/10/24 18:45:18]

Added TODO, filed https://bugs.chromium.org/p/chromium/issues/detail?id=658800.

+      if (document)

[ojan, 2016/10/21 21:33:06]

This can early return if the document->hasReceivedUserGesture(), right? No need
to walk up the ancestor chain on every keypress. :)

[Nate Chapin, 2016/10/21 21:36:49]

Technically it's not guaranteed that, if a Document has its user gesture flag
set, that all ancestors will have it set, because the flag can be cleared by the
history-entry-requires-user-gesture experiment. If the experiment is removed,
then I agree, that optimization makes sense.

[Rick Byers, 2016/10/24 18:30:46]

If there's no good way to avoid this then I'm not too worried about it.  I don't
think we should ever be taking a token any more frequently than "response"
scenarios (eg. each key press, not each and every mouse/touchmove which is
"animation"), and walking the frame chain should always be quite cheap.

+        document->setHasReceivedUserGesture();
+    }
+  }
+};
+
+}  // namespace blink
+
+#endif  // DocumentUserGestureToken_h