Move SurfaceSequenceGenerator => cc/surfaces

cc/BUILD.gn

Index: cc/BUILD.gn
diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index 225b6a8e11b0d0467355b8353b06df340019dc91..1ff189c32a2697120819963790b28eb75bb8c91c 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn
@@ -559,8 +559,6 @@ component("cc") {
     "trees/scroll_node.h",
     "trees/single_thread_proxy.cc",
     "trees/single_thread_proxy.h",
-    "trees/surface_sequence_generator.cc",
-    "trees/surface_sequence_generator.h",
     "trees/swap_promise_manager.cc",
     "trees/swap_promise_manager.h",
     "trees/swap_promise_monitor.cc",
@@ -978,7 +976,6 @@ test("cc_unittests") {
     "trees/occlusion_unittest.cc",
     "trees/property_tree_unittest.cc",
     "trees/proxy_common_unittest.cc",
-    "trees/surface_sequence_generator_unittest.cc",
     "trees/swap_promise_manager_unittest.cc",
     "trees/tree_synchronizer_unittest.cc",
 
@@ -990,6 +987,7 @@ test("cc_unittests") {
     "surfaces/surface_factory_unittest.cc",
     "surfaces/surface_hittest_unittest.cc",
     "surfaces/surface_manager_unittest.cc",
+    "surfaces/surface_sequence_generator_unittest.cc",
     "surfaces/surface_unittest.cc",
     "surfaces/surfaces_pixeltest.cc",