WIP Hittest Component.

components/viz/hit_test/hit_test_aggregator.h

Index: components/viz/hit_test/hit_test_aggregator.h
diff --git a/components/viz/hit_test/hit_test_aggregator.h b/components/viz/hit_test/hit_test_aggregator.h
new file mode 100644
index 0000000000000000000000000000000000000000..ead3b417da82fc298619ad56d7826f1422fc4470
--- /dev/null
+++ b/components/viz/hit_test/hit_test_aggregator.h
@@ -0,0 +1,91 @@
+// 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_AGGREGATOR_H_
+#define COMPONENTS_VIZ_HIT_TEST_HIT_TEST_AGGREGATOR_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/display_hit_test_data.h"
+#include "components/viz/hit_test/hit_test_export.h"
+#include "components/viz/hit_test/public/interfaces/hit_test_data.mojom.h"
+#include "ui/gfx/geometry/quad_f.h"
+
+namespace viz {
+
+namespace hit_test {
+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
+// will be true after the mus process split.
+

[rjkroege, 2017/06/07 21:19:06]

nit: remove blank?

And: since when can you preserve HitTestDataPtr? It's a unique_ptr under the
hood yes? You will need a ref_ptr wrapper so that you can have a reference to it
in both the pending_ and active_ maps?

[gklassen, 2017/06/08 20:33:21]

Yes - although I believe it may be possible to move objects from pending to
active lists rather than keep copies.  I have made changes to reflect this. 

+typedef std::map<cc::SurfaceId, hit_test::mojom::HitTestDataPtr> HitTestDataMap;
+
+class HIT_TEST_EXPORT HitTestAggregator : public cc::SurfaceObserver {
+  friend class hit_test::test::HitTestAggregatorTest;
+
+ public:
+  HitTestAggregator();
+  ~HitTestAggregator();
+
+  // Called when HitTestData is submitted along with every call
+  // to SubmitCompositorFrame.  This is collected in pending_ until
+  // surfaces are aggregated and put on screen.
+  void SubmitHitTestData(hit_test::mojom::HitTestDataPtr hit_test_data);

[rjkroege, 2017/06/07 21:19:06]

Need a TODO for what to do if the submitted data is invalid.

[gklassen, 2017/06/08 20:33:21]

Good call. TODO added to the implementaiton. Done.

+
+  // Called when surfaces have been aggregated.  Used to aggregate
+  // HitTestData into the tree structure in shared memory and used
+  // for event targetting.
+  void Aggregate(cc::SurfaceId display_surface_id);
+
+  // Called at BeginFrame to swap buffers in shared memory.
+  void Swap();
+
+  // SurfaceObserver
+  void OnSurfaceCreated(const cc::SurfaceInfo& surface_info) override {}
+  void OnSurfaceDestroyed(const cc::SurfaceId& surface_id) override {}
+  void OnSurfaceDamaged(const cc::SurfaceId& surface_id,
+                        const cc::BeginFrameAck& ack,
+                        bool* changed) override {}
+  void OnSurfaceDiscarded(const cc::SurfaceId& surface_id) override;
+  void OnSurfaceDamageExpected(const cc::SurfaceId& surface_id,
+                               const cc::BeginFrameArgs& args) override {}
+

[rjkroege, 2017/06/07 21:19:06]

remove blank

[gklassen, 2017/06/08 20:33:21]

Done.

+  // Called when a surface has been aggregated and added to the
+  // display frame.  HitTestData objects are held but ignored until
+  // this happens.  HitTestData for the surface is copied from pending_
+  // to active_ in this method.
+  void OnSurfaceWillDraw(const cc::SurfaceId& surface_id) override;
+
+  DisplayHitTestData* display_hit_test_data_;

[rjkroege, 2017/06/07 21:19:05]

Does it need to be public? Have an accessor?

[gklassen, 2017/06/08 20:33:21]

Good call. Done.

+
+  DisplayHitTestRegion* GetCurrentRegions();
+
+ private:
+  HitTestDataMap pending_;
+  HitTestDataMap active_;
+
+  void AllocateDisplayHitTestData();

[rjkroege, 2017/06/07 21:19:05]

method comments would be convenient for people unfamiliar with your code.

[gklassen, 2017/06/08 20:33:21]

Agreed. Done.

+  void AllocateDisplayHitTestData(int size);
+
+  int GetBackIndex();
+
+  int Append(cc::SurfaceId surface_id, int index);
+  int Append(const hit_test::mojom::HitTestRegionPtr& region, int index);
+};
+
+}  // namespace viz
+
+#endif  //  COMPONENTS_VIZ_HIT_TEST_HIT_TEST_AGGREGATOR_H_