cc: Add checker-imaging support to TileManager.

cc/BUILD.gn

Index: cc/BUILD.gn
diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index 1d17fc86c3debe62f4a162b4873b81e55b998ba6..ccce3d7dc5ba662aa348981553b9d7ad732a0704 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn
@@ -392,6 +392,8 @@ cc_component("cc") {
     "scheduler/scheduler_state_machine.cc",
     "scheduler/scheduler_state_machine.h",
     "scheduler/video_frame_controller.h",
+    "tiles/checker_image_tracker.cc",
+    "tiles/checker_image_tracker.h",
     "tiles/decoded_image_tracker.cc",
     "tiles/decoded_image_tracker.h",
     "tiles/eviction_tile_priority_queue.cc",
@@ -423,6 +425,7 @@ cc_component("cc") {
     "tiles/tile_draw_info.h",
     "tiles/tile_manager.cc",
     "tiles/tile_manager.h",
+    "tiles/tile_manager_settings.h",
     "tiles/tile_priority.cc",
     "tiles/tile_priority.h",
     "tiles/tile_task_manager.cc",
@@ -832,6 +835,7 @@ cc_test("cc_unittests") {
     "test/mock_helper_unittest.cc",
     "test/ordered_simple_task_runner_unittest.cc",
     "test/test_web_graphics_context_3d_unittest.cc",
+    "tiles/checker_image_tracker_unittest.cc",
     "tiles/decoded_image_tracker_unittest.cc",
     "tiles/gpu_image_decode_cache_unittest.cc",
     "tiles/image_controller_unittest.cc",