WIP Hittest Component.

components/viz/hit_test/display_hit_test_data.h

+// Copyright 2017 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 COMPONENTS_VIZ_HIT_TEST_HIT_TEST_DATA_H_
+#define COMPONENTS_VIZ_HIT_TEST_HIT_TEST_DATA_H_
+
+#include <stdint.h>
+
+#include <map>
+#include <memory>
+
+#include "cc/surfaces/surface_id.h"
+#include "cc/surfaces/surface_observer.h"
+#include "components/viz/hit_test/hit_test_export.h"
+#include "components/viz/hit_test/public/interfaces/hit_test_data.mojom.h"
+#include "hit_test_aggregator.h"
+#include "ui/gfx/geometry/quad_f.h"
+
+namespace viz {
+
+// DiplayHitTestData contains the hit_test data for the Display.
+//
+// It is designed to be in shared memory so that the viz process can
+// write the hit_test data, and other processes can read without

[rjkroege, 2017/06/09 15:47:08]

nit: only one process. The browser / ws.

[gklassen, 2017/06/12 16:30:41]

A very welcome nit.  Thank you. Done.

+// process hops.
+//
+// One instance of this class contains a double buffer of entries -

[rjkroege, 2017/06/09 15:47:08]

there is a need to add a TODO about setting up the shared memory scheme?

because mus is currently one process, we can add that later.

[gklassen, 2017/06/12 16:30:41]

Added by abstracting allocation on your suggestion. Done.

+// the viz process will write into one half while client processes read from
+// the other.  read_offset_ is used to swap buffers atomically.
+
+// the child_count_ of the last region in the list is set to
+constexpr int kEndOfList = -1;
+
+struct DisplayHitTestRegion {
+  cc::FrameSinkId frame_sink_id_;
+  hit_test::mojom::HitTestRegionFlags flags_;
+  gfx::Rect rect_;
+  gfx::Transform transform_;
+  int child_count_;
+};
+
+struct DisplayHitTestData {
+  int size_;
+  base::subtle::Atomic32 read_offset_;

[rjkroege, 2017/06/09 15:47:07]

this is communication from a less-trusted process to a more trusted one. We need
a security review discussion early next week. I think that's an AI for me.

[gklassen, 2017/06/12 16:30:41]

Acknowledged.

+  DisplayHitTestRegion regions_[];
+};
+
+}  // namespace viz
+
+#endif  //  COMPONENTS_VIZ_HIT_TEST_HIT_TEST_DATA_H_