Implement HitTestAggregator

components/viz/service/BUILD.gn

Index: components/viz/service/BUILD.gn
diff --git a/components/viz/service/BUILD.gn b/components/viz/service/BUILD.gn
index ecb8291d9c668d27a0d4eae05784858f362ccd8a..962d1113a8f16cae5beac8ac49ce657a69a78b96 100644
--- a/components/viz/service/BUILD.gn
+++ b/components/viz/service/BUILD.gn
@@ -37,6 +37,8 @@ component("service") {
     "frame_sinks/gpu_root_compositor_frame_sink.h",
     "frame_sinks/mojo_frame_sink_manager.cc",
     "frame_sinks/mojo_frame_sink_manager.h",
+    "hit_test/hit_test_aggregator.cc",
+    "hit_test/hit_test_aggregator.h",
     "viz_service_export.h",
   ]
 
@@ -54,6 +56,7 @@ component("service") {
     "//gpu/command_buffer/common",
     "//gpu/ipc:command_buffer",
     "//gpu/ipc/common:surface_handle_type",
+    "//services/viz/public/interfaces",
     "//skia",
     "//ui/display/types",
     "//ui/gfx",
@@ -98,6 +101,7 @@ source_set("unit_tests") {
   sources = [
     "display_compositor/buffer_queue_unittest.cc",
     "display_compositor/host_shared_bitmap_manager_unittest.cc",
+    "hit_test/hit_test_aggregator_unittest.cc",
   ]
 
   if (!use_aura && !is_mac) {
@@ -118,6 +122,7 @@ source_set("unit_tests") {
     "//gpu/command_buffer/client:gles2_implementation",
     "//gpu/ipc:gl_in_process_context",
     "//media",
+    "//services/viz/public/interfaces",
     "//skia",
     "//testing/gmock",
     "//testing/gtest",