Communicate whether passive event listeners exist to cc.

cc/input/event_listener_properties.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 CC_INPUT_EVENT_LISTENER_PROPERTIES_H_
+#define CC_INPUT_EVENT_LISTENER_PROPERTIES_H_
+
+namespace cc {
+
+struct EventListenerProperties {
+  enum : uint32_t { kNone = 0 };
+  enum : uint32_t { kBlocking = 1 << 0 };
+  enum : uint32_t { kPassive = 1 << 1 };
+  enum : uint32_t { kMax = kPassive | kBlocking };
+};
+
+}  // namespace cc
+
+#endif  // CC_INPUT_EVENT_LISTENER_PROPERTIES_H_