Add viz-host HitTestQuery.

components/viz/host/hit_test/hit_test_query.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_HOST_HIT_TEST_HIT_TEST_QUERY_H_
+#define COMPONENTS_VIZ_HOST_HIT_TEST_HIT_TEST_QUERY_H_
+
+#include <vector>
+
+#include "base/macros.h"
+#include "components/viz/common/hit_test/display_hit_test_data.h"
+#include "ui/gfx/geometry/point.h"
+
+namespace viz {
+namespace hit_test {
+
+struct Target {
+  cc::FrameSinkId id;

[varkha, 2017/06/26 19:25:30]

nit: whitespace after.

[riajiang, 2017/06/27 15:51:45]

Hmm I tried adding whitespace but git cl format would remove that?

+  // |location_in_target| is in the coordinate system of the target FrameSinkId.

[varkha, 2017/06/26 19:25:30]

nit: maybe just "Coordinates in the coordinate system ...", no need to repeat
the member name.

[riajiang, 2017/06/27 15:51:45]

Done.

+  gfx::Point location_in_target;

[varkha, 2017/06/26 19:25:30]

nit: whitespace after.

[sadrul, 2017/06/27 03:37:54]

Might make sense to make this a gfx::PointF.

[riajiang, 2017/06/27 15:51:45]

Transform::TransformPoint only supports Point and Point3F? How about changing to
Point3F when we add support for 3d space cases?

+  // Different flags are defined in services/viz/public/interfaces/
+  // hit_test_data.mojom.

[varkha, 2017/06/26 19:25:30]

Is this in services/viz/hit_test/public/interfaces/hit_test_data.mojom in [1]?

[1] = https://codereview.chromium.org/2938953002

[riajiang, 2017/06/27 15:51:45]

Yes, it's in that CL.

+  uint32_t flags;
+};
+
+// Finds the target for a given location based on DisplayHitTestData aggreated

[sadrul, 2017/06/27 03:37:55]

*aggregated

[riajiang, 2017/06/27 15:51:45]

Done.

+// by HitTestComponent.
+// TODO(riajiang): Handle 3d space cases correctly.
+class HitTestQuery {
+ public:
+  HitTestQuery();
+  ~HitTestQuery();
+
+  // TODO(riajiang): Read from shmem directly once it's set up and delete this
+  // function. For now, use fake data.
+  void set_display_hit_test_data_list(
+      DisplayHitTestData display_hit_test_data_list) {
+    display_hit_test_data_list_ = std::move(display_hit_test_data_list);
+  }
+
+  // Find Target for |location_in_root|, including the FrameSinkId of the

[varkha, 2017/06/26 19:25:30]

nit: Finds

[riajiang, 2017/06/27 15:51:45]

Done.

+  // target, updated location in the coordinate system of the target and
+  // hit-test flags for the target.
+  Target FindTargetForLocation(const gfx::Point& location_in_root);
+
+ private:
+  // Helper function to find |target| for |location_in_region| in the |region|,
+  // returns true if a target is found and false otherwise.
+  bool FindTargetForLocationInRegion(const gfx::Point& location_in_region,
+                                     DisplayHitTestDataRegion* region,
+                                     Target* target);

[sadrul, 2017/06/27 03:37:55]

Should this be a const method?

[riajiang, 2017/06/27 15:51:45]

Done.

+
+  DisplayHitTestData display_hit_test_data_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(HitTestQuery);
+};
+
+}  // namespace hit_test
+}  // namespace viz
+
+#endif  // COMPONENTS_VIZ_HOST_HIT_TEST_HIT_TEST_QUERY_H_