Add viz-host HitTestQuery.

components/viz/host/hit_test/hit_test_query_unittest.cc

Index: components/viz/host/hit_test/hit_test_query_unittest.cc
diff --git a/components/viz/host/hit_test/hit_test_query_unittest.cc b/components/viz/host/hit_test/hit_test_query_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..35182b43d13407b3f5e44a4cef85ecb928dda94e
--- /dev/null
+++ b/components/viz/host/hit_test/hit_test_query_unittest.cc
@@ -0,0 +1,526 @@
+// 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.
+
+#include "components/viz/host/hit_test/hit_test_query.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace viz {
+namespace hit_test {
+namespace test {
+
+class HitTestQueryTest : public testing::Test {
+ public:
+  HitTestQueryTest() {}
+  ~HitTestQueryTest() override {}
+
+  HitTestQuery hit_test_query_;
+
+ private:
+  // testing::Test:
+  void SetUp() override {}
+  void TearDown() override {}
+
+  DISALLOW_COPY_AND_ASSIGN(HitTestQueryTest);
+};
+
+// One surface.
+//
+//  +e---------+
+//  |          |
+//  |          |
+//  |          |
+//  +----------+
+//
+TEST_F(HitTestQueryTest, OneSurface) {
+  cc::FrameSinkId e_id = cc::FrameSinkId(1, 1);
+  gfx::Rect e_bounds = gfx::Rect(0, 0, 600, 600);
+  gfx::Transform transform_e_to_e;
+  DisplayHitTestDataList display_hit_test_data_list = {
+      {e_id, e_bounds, transform_e_to_e, 1 /* HIT_TEST_MINE */, 0}  // e
+  };
+  hit_test_query_.set_display_hit_test_data_list(display_hit_test_data_list);
+
+  // All points are in e's coordinate system when we reach this case.
+  gfx::Point point1(1, 1);
+  gfx::Point point2(600, 600);
+  gfx::Point point3(0, 0);
+
+  Target target1 = hit_test_query_.FindTargetForLocation(point1);
+  EXPECT_EQ(e_id, target1.id);
+  EXPECT_EQ(point1, target1.location_in_target);
+  EXPECT_TRUE(target1.flags);
+
+  // point2 is on the bounds of e so no target found.
+  Target target2 = hit_test_query_.FindTargetForLocation(point2);
+  EXPECT_EQ(cc::FrameSinkId(), target2.id);
+  EXPECT_EQ(gfx::Point(), target2.location_in_target);
+  EXPECT_FALSE(target2.flags);
+
+  // There's a valid Target for point3, see Rect::Contains.
+  Target target3 = hit_test_query_.FindTargetForLocation(point3);
+  EXPECT_EQ(e_id, target3.id);
+  EXPECT_EQ(point3, target3.location_in_target);
+  EXPECT_TRUE(target3.flags);
+}
+
+// One embedder with two children.
+//
+//  +e------------+     Point   maps to
+//  | +c1-+ +c2---|     -----   -------
+//  |1|   | |     |      1        e
+//  | | 2 | | 3   | 4    2        c1
+//  | +---+ |     |      3        c2
+//  +-------------+      4        none
+//
+TEST_F(HitTestQueryTest, OneEmbedderTwoChildren) {
+  cc::FrameSinkId e_id = cc::FrameSinkId(1, 1);
+  cc::FrameSinkId c1_id = cc::FrameSinkId(2, 2);
+  cc::FrameSinkId c2_id = cc::FrameSinkId(3, 3);
+  gfx::Rect e_bounds_in_e = gfx::Rect(0, 0, 600, 600);
+  gfx::Rect c1_bounds_in_e = gfx::Rect(0, 0, 200, 200);
+  gfx::Rect c2_bounds_in_e = gfx::Rect(0, 0, 400, 400);
+  gfx::Transform transform_e_to_e, transform_e_to_c1, transform_e_to_c2;
+  transform_e_to_c1.Translate(-100, -100);
+  transform_e_to_c2.Translate(-300, -300);
+  DisplayHitTestDataList display_hit_test_data_list = {
+      {e_id, e_bounds_in_e, transform_e_to_e, 1 /* HIT_TEST_MINE */, 2},  // e
+      {c1_id, c1_bounds_in_e, transform_e_to_c1, 1 /* HIT_TEST_MINE */,
+       0},  // c1
+      {c2_id, c2_bounds_in_e, transform_e_to_c2, 1 /* HIT_TEST_MINE */,
+       0}  // c2
+  };
+  hit_test_query_.set_display_hit_test_data_list(display_hit_test_data_list);
+
+  // All points are in e's coordinate system when we reach this case.
+  gfx::Point point1(99, 200);
+  gfx::Point point2(150, 150);
+  gfx::Point point3(400, 400);
+  gfx::Point point4(650, 350);
+
+  Target target1 = hit_test_query_.FindTargetForLocation(point1);
+  EXPECT_EQ(e_id, target1.id);
+  EXPECT_EQ(point1, target1.location_in_target);
+  EXPECT_TRUE(target1.flags);
+
+  Target target2 = hit_test_query_.FindTargetForLocation(point2);
+  EXPECT_EQ(c1_id, target2.id);
+  EXPECT_EQ(gfx::Point(50, 50), target2.location_in_target);
+  EXPECT_TRUE(target2.flags);
+
+  Target target3 = hit_test_query_.FindTargetForLocation(point3);
+  EXPECT_EQ(c2_id, target3.id);
+  EXPECT_EQ(gfx::Point(100, 100), target3.location_in_target);
+  EXPECT_TRUE(target3.flags);
+
+  Target target4 = hit_test_query_.FindTargetForLocation(point4);
+  EXPECT_EQ(cc::FrameSinkId(), target4.id);
+  EXPECT_EQ(gfx::Point(), target4.location_in_target);
+  EXPECT_FALSE(target4.flags);
+}
+
+// One embedder with a rotated child.
+TEST_F(HitTestQueryTest, OneEmbedderRotatedChild) {
+  cc::FrameSinkId e_id = cc::FrameSinkId(1, 1);
+  cc::FrameSinkId c_id = cc::FrameSinkId(2, 2);
+  gfx::Rect e_bounds_in_e = gfx::Rect(0, 0, 600, 600);
+  gfx::Rect c_bounds_in_e = gfx::Rect(0, 0, 1000, 1000);
+  gfx::Transform transform_e_to_e, transform_e_to_c;
+  transform_e_to_c.Translate(-100, -100);
+  transform_e_to_c.Skew(2, 3);
+  transform_e_to_c.Scale(.5f, .7f);
+
+  DisplayHitTestDataList display_hit_test_data_list = {
+      {e_id, e_bounds_in_e, transform_e_to_e, 1 /* HIT_TEST_MINE */, 1},  // e
+      {c_id, c_bounds_in_e, transform_e_to_c, 1 /* HIT_TEST_MINE */, 0}   // c
+  };
+  hit_test_query_.set_display_hit_test_data_list(display_hit_test_data_list);
+
+  // All points are in e's coordinate system when we reach this case.
+  gfx::Point point1(150, 120);  // Point(-22, -12) after transform.
+  gfx::Point point2(550, 400);  // Point(185, 194) after transform.
+
+  Target target1 = hit_test_query_.FindTargetForLocation(point1);
+  EXPECT_EQ(e_id, target1.id);
+  EXPECT_EQ(point1, target1.location_in_target);
+  EXPECT_TRUE(target1.flags);
+
+  Target target2 = hit_test_query_.FindTargetForLocation(point2);
+  EXPECT_EQ(c_id, target2.id);
+  EXPECT_EQ(gfx::Point(185, 194), target2.location_in_target);
+  EXPECT_TRUE(target2.flags);
+}
+
+// One embedder with a clipped child with a tab and transparent background.
+//
+//  +e-------------+
+//  |   +c---------|     Point   maps to
+//  | 1 |+a--+     |     -----   -------
+//  |   || 2 |  3  |       1        e
+//  |   |+b--------|       2        a
+//  |   ||         |       3        e ( transparent area in c )
+//  |   ||   4     |       4        b
+//  +--------------+
+//
+TEST_F(HitTestQueryTest, ClippedChildWithTabAndTransparentBackground) {
+  cc::FrameSinkId e_id = cc::FrameSinkId(1, 1);
+  cc::FrameSinkId c_id = cc::FrameSinkId(2, 2);
+  cc::FrameSinkId a_id = cc::FrameSinkId(3, 3);
+  cc::FrameSinkId b_id = cc::FrameSinkId(4, 4);
+  gfx::Rect e_bounds_in_e = gfx::Rect(0, 0, 600, 600);
+  gfx::Rect c_bounds_in_e = gfx::Rect(0, 0, 800, 800);
+  gfx::Rect a_bounds_in_c = gfx::Rect(0, 0, 200, 100);
+  gfx::Rect b_bounds_in_c = gfx::Rect(0, 0, 800, 600);
+  gfx::Transform transform_e_to_e, transform_e_to_c, transform_c_to_a,
+      transform_c_to_b;
+  transform_e_to_c.Translate(-200, -100);
+  transform_c_to_b.Translate(0, -100);
+  DisplayHitTestDataList display_hit_test_data_list = {
+      {e_id, e_bounds_in_e, transform_e_to_e, 1 /* HIT_TEST_MINE */, 3},    // e
+      {c_id, c_bounds_in_e, transform_e_to_c, 0 /* HIT_TEST_IGNORE */, 2},  // c
+      {a_id, a_bounds_in_c, transform_c_to_a, 1 /* HIT_TEST_MINE */, 0},    // a
+      {b_id, b_bounds_in_c, transform_c_to_b, 1 /* HIT_TEST_MINE */, 0}     // b
+  };
+  hit_test_query_.set_display_hit_test_data_list(display_hit_test_data_list);
+
+  // All points are in e's coordinate system when we reach this case.
+  gfx::Point point1(1, 1);
+  gfx::Point point2(202, 102);
+  gfx::Point point3(403, 103);
+  gfx::Point point4(202, 202);
+
+  Target target1 = hit_test_query_.FindTargetForLocation(point1);
+  EXPECT_EQ(e_id, target1.id);
+  EXPECT_EQ(point1, target1.location_in_target);
+  EXPECT_TRUE(target1.flags);
+
+  Target target2 = hit_test_query_.FindTargetForLocation(point2);
+  EXPECT_EQ(a_id, target2.id);
+  EXPECT_EQ(gfx::Point(2, 2), target2.location_in_target);
+  EXPECT_TRUE(target2.flags);
+
+  Target target3 = hit_test_query_.FindTargetForLocation(point3);
+  EXPECT_EQ(e_id, target3.id);
+  EXPECT_EQ(point3, target3.location_in_target);
+  EXPECT_TRUE(target3.flags);
+
+  Target target4 = hit_test_query_.FindTargetForLocation(point4);
+  EXPECT_EQ(b_id, target4.id);
+  EXPECT_EQ(gfx::Point(2, 2), target4.location_in_target);
+  EXPECT_TRUE(target4.flags);
+}
+
+// One embedder with a clipped child with a tab and transparent background, and
+// a child d under that.
+//
+//  +e-------------+
+//  |      +d------|
+//  |   +c-|-------|     Point   maps to
+//  | 1 |+a|-+     |     -----   -------
+//  |   || 2 |  3  |       1        e
+//  |   |+b|-------|       2        a
+//  |   || |       |       3        d
+//  |   || | 4     |       4        b
+//  +--------------+
+//
+TEST_F(HitTestQueryTest, ClippedChildWithChildUnderneath) {
+  cc::FrameSinkId e_id = cc::FrameSinkId(1, 1);
+  cc::FrameSinkId c_id = cc::FrameSinkId(2, 2);
+  cc::FrameSinkId a_id = cc::FrameSinkId(3, 3);
+  cc::FrameSinkId b_id = cc::FrameSinkId(4, 4);
+  cc::FrameSinkId d_id = cc::FrameSinkId(5, 5);
+  gfx::Rect e_bounds_in_e = gfx::Rect(0, 0, 600, 600);
+  gfx::Rect c_bounds_in_e = gfx::Rect(0, 0, 800, 800);
+  gfx::Rect a_bounds_in_c = gfx::Rect(0, 0, 200, 100);
+  gfx::Rect b_bounds_in_c = gfx::Rect(0, 0, 800, 600);
+  gfx::Rect d_bounds_in_e = gfx::Rect(0, 0, 800, 800);
+  gfx::Transform transform_e_to_e, transform_e_to_c, transform_c_to_a,
+      transform_c_to_b, transform_e_to_d;
+  transform_e_to_c.Translate(-200, -100);
+  transform_c_to_b.Translate(0, -100);
+  transform_e_to_d.Translate(-400, -50);
+  DisplayHitTestDataList display_hit_test_data_list = {
+      {e_id, e_bounds_in_e, transform_e_to_e, 1 /* HIT_TEST_MINE */, 4},    // e
+      {c_id, c_bounds_in_e, transform_e_to_c, 0 /* HIT_TEST_IGNORE */, 2},  // c
+      {a_id, a_bounds_in_c, transform_c_to_a, 1 /* HIT_TEST_MINE */, 0},    // a
+      {b_id, b_bounds_in_c, transform_c_to_b, 1 /* HIT_TEST_MINE */, 0},    // b
+      {d_id, d_bounds_in_e, transform_e_to_d, 1 /* HIT_TEST_MINE */, 0}     // d
+  };
+  hit_test_query_.set_display_hit_test_data_list(display_hit_test_data_list);
+
+  // All points are in e's coordinate system when we reach this case.
+  gfx::Point point1(1, 1);
+  gfx::Point point2(202, 102);
+  gfx::Point point3(450, 150);
+  gfx::Point point4(202, 202);
+
+  Target target1 = hit_test_query_.FindTargetForLocation(point1);
+  EXPECT_EQ(e_id, target1.id);
+  EXPECT_EQ(point1, target1.location_in_target);
+  EXPECT_TRUE(target1.flags);
+
+  Target target2 = hit_test_query_.FindTargetForLocation(point2);
+  EXPECT_EQ(a_id, target2.id);
+  EXPECT_EQ(gfx::Point(2, 2), target2.location_in_target);
+  EXPECT_TRUE(target2.flags);
+
+  Target target3 = hit_test_query_.FindTargetForLocation(point3);
+  EXPECT_EQ(d_id, target3.id);
+  EXPECT_EQ(gfx::Point(50, 100), target3.location_in_target);
+  EXPECT_TRUE(target3.flags);
+
+  Target target4 = hit_test_query_.FindTargetForLocation(point4);
+  EXPECT_EQ(b_id, target4.id);
+  EXPECT_EQ(gfx::Point(2, 2), target4.location_in_target);
+  EXPECT_TRUE(target4.flags);
+}
+
+// One embedder with two clipped children with a tab and transparent background.
+//
+//  +e-------------+
+//  |   +c1--------|     Point   maps to
+//  | 1 |+a--+     |     -----   -------
+//  |   || 2 |  3  |       1        e
+//  |   |+b--------|       2        a
+//  |   ||         |       3        e ( transparent area in c1 )
+//  |   ||   4     |       4        b
+//  |   +----------|       5        g
+//  |   +c2--------|       6        e ( transparent area in c2 )
+//  |   |+g--+     |       7        h
+//  |   || 5 |  6  |
+//  |   |+h--------|
+//  |   ||         |
+//  |   ||   7     |
+//  +--------------+
+//
+TEST_F(HitTestQueryTest, ClippedChildrenWithTabAndTransparentBackground) {
+  cc::FrameSinkId e_id = cc::FrameSinkId(1, 1);
+  cc::FrameSinkId c1_id = cc::FrameSinkId(2, 2);
+  cc::FrameSinkId a_id = cc::FrameSinkId(3, 3);
+  cc::FrameSinkId b_id = cc::FrameSinkId(4, 4);
+  cc::FrameSinkId c2_id = cc::FrameSinkId(5, 5);
+  cc::FrameSinkId g_id = cc::FrameSinkId(6, 6);
+  cc::FrameSinkId h_id = cc::FrameSinkId(7, 7);
+  gfx::Rect e_bounds_in_e = gfx::Rect(0, 0, 600, 1200);
+  gfx::Rect c1_bounds_in_e = gfx::Rect(0, 0, 800, 500);
+  gfx::Rect a_bounds_in_c1 = gfx::Rect(0, 0, 200, 100);
+  gfx::Rect b_bounds_in_c1 = gfx::Rect(0, 0, 800, 400);
+  gfx::Rect c2_bounds_in_e = gfx::Rect(0, 0, 800, 500);
+  gfx::Rect g_bounds_in_c2 = gfx::Rect(0, 0, 200, 100);
+  gfx::Rect h_bounds_in_c2 = gfx::Rect(0, 0, 800, 800);
+  gfx::Transform transform_e_to_e, transform_e_to_c1, transform_c1_to_a,
+      transform_c1_to_b, transform_e_to_c2, transform_c2_to_g,
+      transform_c2_to_h;
+  transform_e_to_c1.Translate(-200, -100);
+  transform_c1_to_b.Translate(0, -100);
+  transform_e_to_c2.Translate(-200, -700);
+  transform_c2_to_h.Translate(0, -100);
+  DisplayHitTestDataList display_hit_test_data_list = {
+      {e_id, e_bounds_in_e, transform_e_to_e, 1 /* HIT_TEST_MINE */, 6},  // e
+      {c1_id, c1_bounds_in_e, transform_e_to_c1, 0 /* HIT_TEST_IGNORE */,
+       2},  // c1
+      {a_id, a_bounds_in_c1, transform_c1_to_a, 1 /* HIT_TEST_MINE */, 0},  // a
+      {b_id, b_bounds_in_c1, transform_c1_to_b, 1 /* HIT_TEST_MINE */, 0},  // b
+      {c2_id, c2_bounds_in_e, transform_e_to_c2, 0 /* HIT_TEST_IGNORE */,
+       2},  // c2
+      {g_id, g_bounds_in_c2, transform_c2_to_g, 1 /* HIT_TEST_MINE */, 0},  // g
+      {h_id, h_bounds_in_c2, transform_c2_to_h, 1 /* HIT_TEST_MINE */, 0}   // h
+  };
+  hit_test_query_.set_display_hit_test_data_list(display_hit_test_data_list);
+
+  // All points are in e's coordinate system when we reach this case.
+  gfx::Point point1(1, 1);
+  gfx::Point point2(202, 102);
+  gfx::Point point3(403, 103);
+  gfx::Point point4(202, 202);
+  gfx::Point point5(250, 750);
+  gfx::Point point6(450, 750);
+  gfx::Point point7(350, 1100);
+
+  Target target1 = hit_test_query_.FindTargetForLocation(point1);
+  EXPECT_EQ(e_id, target1.id);
+  EXPECT_EQ(point1, target1.location_in_target);
+  EXPECT_TRUE(target1.flags);
+
+  Target target2 = hit_test_query_.FindTargetForLocation(point2);
+  EXPECT_EQ(a_id, target2.id);
+  EXPECT_EQ(gfx::Point(2, 2), target2.location_in_target);
+  EXPECT_TRUE(target2.flags);
+
+  Target target3 = hit_test_query_.FindTargetForLocation(point3);
+  EXPECT_EQ(e_id, target3.id);
+  EXPECT_EQ(point3, target3.location_in_target);
+  EXPECT_TRUE(target3.flags);
+
+  Target target4 = hit_test_query_.FindTargetForLocation(point4);
+  EXPECT_EQ(b_id, target4.id);
+  EXPECT_EQ(gfx::Point(2, 2), target4.location_in_target);
+  EXPECT_TRUE(target4.flags);
+
+  Target target5 = hit_test_query_.FindTargetForLocation(point5);
+  EXPECT_EQ(g_id, target5.id);
+  EXPECT_EQ(gfx::Point(50, 50), target5.location_in_target);
+  EXPECT_TRUE(target5.flags);
+
+  Target target6 = hit_test_query_.FindTargetForLocation(point6);
+  EXPECT_EQ(e_id, target6.id);
+  EXPECT_EQ(point6, target6.location_in_target);
+  EXPECT_TRUE(target6.flags);
+
+  Target target7 = hit_test_query_.FindTargetForLocation(point7);
+  EXPECT_EQ(h_id, target7.id);
+  EXPECT_EQ(gfx::Point(150, 300), target7.location_in_target);
+  EXPECT_TRUE(target7.flags);
+}
+
+// Children that are multiple layers deep.
+//
+//  +e--------------------+
+//  |          +c2--------|     Point   maps to
+//  | +c1------|----+     |     -----   -------
+//  |1| +a-----|---+|     |       1        e
+//  | | |+b----|--+||     |       2        g
+//  | | ||+g--+|  |||     |       3        b
+//  | | ||| 2 || 3|||  4  |       4        c2
+//  | | ||+---+|  |||     |
+//  | | |+-----|--+||     |
+//  | | +------| --+|     |
+//  | +--------|----+     |
+//  +---------------------+
+//
+TEST_F(HitTestQueryTest, MultipleLayerChild) {
+  cc::FrameSinkId e_id = cc::FrameSinkId(1, 1);
+  cc::FrameSinkId c1_id = cc::FrameSinkId(2, 2);
+  cc::FrameSinkId a_id = cc::FrameSinkId(3, 3);
+  cc::FrameSinkId b_id = cc::FrameSinkId(4, 4);
+  cc::FrameSinkId g_id = cc::FrameSinkId(5, 5);
+  cc::FrameSinkId c2_id = cc::FrameSinkId(6, 6);
+  gfx::Rect e_bounds_in_e = gfx::Rect(0, 0, 1000, 1000);
+  gfx::Rect c1_bounds_in_e = gfx::Rect(0, 0, 800, 800);
+  gfx::Rect a_bounds_in_c1 = gfx::Rect(0, 0, 700, 700);
+  gfx::Rect b_bounds_in_a = gfx::Rect(0, 0, 600, 600);
+  gfx::Rect g_bounds_in_b = gfx::Rect(0, 0, 200, 200);
+  gfx::Rect c2_bounds_in_e = gfx::Rect(0, 0, 800, 800);
+  gfx::Transform transform_e_to_e, transform_e_to_c1, transform_c1_to_a,
+      transform_a_to_b, transform_b_to_g, transform_e_to_c2;
+  transform_e_to_c1.Translate(-100, -100);
+  transform_a_to_b.Translate(-50, -30);
+  transform_b_to_g.Translate(-150, -200);
+  transform_e_to_c2.Translate(-400, -50);
+  DisplayHitTestDataList display_hit_test_data_list = {
+      {e_id, e_bounds_in_e, transform_e_to_e, 1 /* HIT_TEST_MINE */, 5},  // e
+      {c1_id, c1_bounds_in_e, transform_e_to_c1, 0 /* HIT_TEST_IGNORE */,
+       3},  // c1
+      {a_id, a_bounds_in_c1, transform_c1_to_a, 1 /* HIT_TEST_MINE */, 2},  // a
+      {b_id, b_bounds_in_a, transform_a_to_b, 1 /* HIT_TEST_MINE */, 1},    // b
+      {g_id, g_bounds_in_b, transform_b_to_g, 1 /* HIT_TEST_MINE */, 0},    // g
+      {c2_id, c2_bounds_in_e, transform_e_to_c2, 1 /* HIT_TEST_MINE */,
+       0}  // c2
+  };
+  hit_test_query_.set_display_hit_test_data_list(display_hit_test_data_list);
+
+  // All points are in e's coordinate system when we reach this case.
+  gfx::Point point1(1, 1);
+  gfx::Point point2(300, 350);
+  gfx::Point point3(550, 350);
+  gfx::Point point4(900, 350);
+
+  Target target1 = hit_test_query_.FindTargetForLocation(point1);
+  EXPECT_EQ(e_id, target1.id);
+  EXPECT_EQ(point1, target1.location_in_target);
+  EXPECT_TRUE(target1.flags);
+
+  Target target2 = hit_test_query_.FindTargetForLocation(point2);
+  EXPECT_EQ(g_id, target2.id);
+  EXPECT_EQ(gfx::Point(0, 20), target2.location_in_target);
+  EXPECT_TRUE(target2.flags);
+
+  Target target3 = hit_test_query_.FindTargetForLocation(point3);
+  EXPECT_EQ(b_id, target3.id);
+  EXPECT_EQ(gfx::Point(400, 220), target3.location_in_target);
+  EXPECT_TRUE(target3.flags);
+
+  Target target4 = hit_test_query_.FindTargetForLocation(point4);
+  EXPECT_EQ(c2_id, target4.id);
+  EXPECT_EQ(gfx::Point(500, 300), target4.location_in_target);
+  EXPECT_TRUE(target4.flags);
+}
+
+// Multiple layers deep of transparent children.
+//
+//  +e--------------------+
+//  |          +c2--------|     Point   maps to
+//  | +c1------|----+     |     -----   -------
+//  |1| +a-----|---+|     |       1        e
+//  | | |+b----|--+||     |       2        e
+//  | | ||+g--+|  |||     |       3        c2
+//  | | ||| 2 || 3|||  4  |       4        c2
+//  | | ||+---+|  |||     |
+//  | | |+-----|--+||     |
+//  | | +------| --+|     |
+//  | +--------|----+     |
+//  +---------------------+
+//
+TEST_F(HitTestQueryTest, MultipleLayerTransparentChild) {
+  cc::FrameSinkId e_id = cc::FrameSinkId(1, 1);
+  cc::FrameSinkId c1_id = cc::FrameSinkId(2, 2);
+  cc::FrameSinkId a_id = cc::FrameSinkId(3, 3);
+  cc::FrameSinkId b_id = cc::FrameSinkId(4, 4);
+  cc::FrameSinkId g_id = cc::FrameSinkId(5, 5);
+  cc::FrameSinkId c2_id = cc::FrameSinkId(6, 6);
+  gfx::Rect e_bounds_in_e = gfx::Rect(0, 0, 1000, 1000);
+  gfx::Rect c1_bounds_in_e = gfx::Rect(0, 0, 800, 800);
+  gfx::Rect a_bounds_in_c1 = gfx::Rect(0, 0, 700, 700);
+  gfx::Rect b_bounds_in_a = gfx::Rect(0, 0, 600, 600);
+  gfx::Rect g_bounds_in_b = gfx::Rect(0, 0, 200, 200);
+  gfx::Rect c2_bounds_in_e = gfx::Rect(0, 0, 800, 800);
+  gfx::Transform transform_e_to_e, transform_e_to_c1, transform_c1_to_a,
+      transform_a_to_b, transform_b_to_g, transform_e_to_c2;
+  transform_e_to_c1.Translate(-100, -100);
+  transform_a_to_b.Translate(-50, -30);
+  transform_b_to_g.Translate(-150, -200);
+  transform_e_to_c2.Translate(-400, -50);
+  DisplayHitTestDataList display_hit_test_data_list = {
+      {e_id, e_bounds_in_e, transform_e_to_e, 1 /* HIT_TEST_MINE */, 5},  // e
+      {c1_id, c1_bounds_in_e, transform_e_to_c1, 0 /* HIT_TEST_IGNORE */,
+       3},  // c1
+      {a_id, a_bounds_in_c1, transform_c1_to_a, 0 /* HIT_TEST_IGNORE */,
+       2},                                                                  // a
+      {b_id, b_bounds_in_a, transform_a_to_b, 0 /* HIT_TEST_IGNORE */, 1},  // b
+      {g_id, g_bounds_in_b, transform_b_to_g, 0 /* HIT_TEST_IGNORE */, 0},  // g
+      {c2_id, c2_bounds_in_e, transform_e_to_c2, 1 /* HIT_TEST_MINE */,
+       0}  // c2
+  };
+  hit_test_query_.set_display_hit_test_data_list(display_hit_test_data_list);
+
+  // All points are in e's coordinate system when we reach this case.
+  gfx::Point point1(1, 1);
+  gfx::Point point2(300, 350);
+  gfx::Point point3(450, 350);
+  gfx::Point point4(900, 350);
+
+  Target target1 = hit_test_query_.FindTargetForLocation(point1);
+  EXPECT_EQ(e_id, target1.id);
+  EXPECT_EQ(point1, target1.location_in_target);
+  EXPECT_TRUE(target1.flags);
+
+  Target target2 = hit_test_query_.FindTargetForLocation(point2);
+  EXPECT_EQ(e_id, target2.id);
+  EXPECT_EQ(point2, target2.location_in_target);
+  EXPECT_TRUE(target2.flags);
+
+  Target target3 = hit_test_query_.FindTargetForLocation(point3);
+  EXPECT_EQ(c2_id, target3.id);
+  EXPECT_EQ(gfx::Point(50, 300), target3.location_in_target);
+  EXPECT_TRUE(target3.flags);
+
+  Target target4 = hit_test_query_.FindTargetForLocation(point4);
+  EXPECT_EQ(c2_id, target4.id);
+  EXPECT_EQ(gfx::Point(500, 300), target4.location_in_target);
+  EXPECT_TRUE(target4.flags);
+}
+
+}  // namespace test
+}  // namespace hit_test
+}  // namespace viz