WIP Hittest Component.

components/viz/hittest/display_hittest_data.h

Index: components/viz/hittest/display_hittest_data.h
diff --git a/components/viz/hittest/display_hittest_data.h b/components/viz/hittest/display_hittest_data.h
new file mode 100644
index 0000000000000000000000000000000000000000..1a09c804ad5add94ec7caf9230b300af06eff2e0
--- /dev/null
+++ b/components/viz/hittest/display_hittest_data.h
@@ -0,0 +1,61 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.

[rjkroege, 2017/06/02 22:45:45]

you need to set the Copyright date to 2017 here and everywhere else

[gklassen, 2017/06/05 21:32:14]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef COMPONENTS_VIZ_HITTEST_HITTEST_AGGREGATOR_H_
+#define COMPONENTS_VIZ_HITTEST_HITTEST_AGGREGATOR_H_
+
+#include <stdint.h>
+
+#include <map>
+#include <memory>
+
+#include "cc/surfaces/surface_id.h"
+#include "cc/surfaces/surface_observer.h"
+#include "components/viz/hittest/hittest_export.h"
+#include "components/viz/hittest/public/interfaces/hittest_data.mojom.h"
+#include "ui/gfx/geometry/quad_f.h"
+
+namespace viz {
+
+namespace test {
+class HittestAggregatorTest;
+}
+
+// Hittest maintains maping between display regions and associated surfaces
+// in shared memory to enable efficient hit testing across processes.
+//
+// This is intended to be created in the viz or GPU process. For mus+ash this

[rjkroege, 2017/06/02 22:45:44]

I'm not sure that the sandbox permits this. You need to verify this with
security team. My understanding is that you'll have to ask the host to make the
shmem segment for you.

[gklassen, 2017/06/05 21:32:14]

Thanks.  Investigating and will have a proposal soon. 

+// will be true after the mus process split.
+
+#define LAST_REGION -2

[rjkroege, 2017/06/02 22:45:45]

enums are preferred.

[gklassen, 2017/06/05 21:32:14]

Done.

+
+class HITTEST_EXPORT DisplayHittestData {

[rjkroege, 2017/06/02 22:45:44]

This need to be a POD class. 

[gklassen, 2017/06/05 21:32:13]

Done.

+  friend class test::HittestAggregatorTest;

[rjkroege, 2017/06/02 22:45:44]

this is conceivably but non ideal. do we have to have this?

+
+ public:
+  DisplayHittestData();
+  ~DisplayHittestData();
+
+  void build(HittestDataMap map, cc::SurfaceId root_surface_id);

[rjkroege, 2017/06/02 22:45:45]

All public Chrome methods are capital letter first names.

[gklassen, 2017/06/05 21:32:13]

Done.

+
+ private:
+  int append(HittestDataMap map, int index, cc::SurfaceId root_surface_id);

[rjkroege, 2017/06/02 22:45:44]

Private methods that are not getters/setters are also capital letter first
names.

[gklassen, 2017/06/05 21:32:13]

Done.

+
+  struct Element {
+    cc.mojom.SurfaceId surface_id_;
+    HittestRegionFlags flags_;
+    gfx.mojom.Rect rect_;

[rjkroege, 2017/06/02 22:45:44]

these do not need to be serialized. You could just use gfx::Rect? And shoudln't
it be gfx::mojom::Rect if you need this? etc.

[gklassen, 2017/06/05 21:32:13]

Done.

+    gfx.mojom.Transform transform_;
+    int child_count_;
+  };
+
+  base::subtle::Atomic32 offset_;

[rjkroege, 2017/06/02 22:45:45]

why?

I see. You are treating this a bit like a command buffer. That's interesting.
I'd suggest sending the offsets via IPC instead of relying on subtle. 

Also, you want the transition to be slaved to the BeginFrame. 

+  int count_;
+  int size_;
+  Element regions_[];

[rjkroege, 2017/06/02 22:45:45]

How are you sizing this? C++ is really very stupid about arrays.

+};
+
+}  // namespace viz
+
+#endif  //  COMPONENTS_VIZ_HITTEST_HITTEST_AGGREGATOR_H_