cc: Split ThreadProxy into ProxyMain and ProxyImpl

cc/BUILD.gn

Index: cc/BUILD.gn
diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index df0083a26967d9389fe34d5938f94ff60c8ccb3f..3be4ebb9b3d28848b32687f46e4b15cac4b73044 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn
@@ -502,7 +502,9 @@ component("cc") {
     "trees/proxy.h",
     "trees/proxy_common.cc",
     "trees/proxy_common.h",
+    "trees/proxy_impl.cc",
     "trees/proxy_impl.h",
+    "trees/proxy_main.cc",
     "trees/proxy_main.h",
     "trees/remote_proto_channel.h",
     "trees/scoped_abort_remaining_swap_promises.h",
@@ -512,8 +514,6 @@ component("cc") {
     "trees/swap_promise_monitor.h",
     "trees/task_runner_provider.cc",
     "trees/task_runner_provider.h",
-    "trees/thread_proxy.cc",
-    "trees/thread_proxy.h",
     "trees/threaded_channel.cc",
     "trees/threaded_channel.h",
     "trees/tree_synchronizer.cc",
@@ -655,6 +655,10 @@ source_set("test_support") {
     "test/pixel_test_software_output_device.h",
     "test/pixel_test_utils.cc",
     "test/pixel_test_utils.h",
+    "test/proxy_impl_for_test.cc",
+    "test/proxy_impl_for_test.h",
+    "test/proxy_main_for_test.cc",
+    "test/proxy_main_for_test.h",
     "test/render_pass_test_utils.cc",
     "test/render_pass_test_utils.h",
     "test/scheduler_test_common.cc",
@@ -677,6 +681,8 @@ source_set("test_support") {
     "test/test_gles2_interface.h",
     "test/test_gpu_memory_buffer_manager.cc",
     "test/test_gpu_memory_buffer_manager.h",
+    "test/test_hooks.cc",
+    "test/test_hooks.h",
     "test/test_image_factory.cc",
     "test/test_image_factory.h",
     "test/test_in_process_context_provider.cc",
@@ -692,6 +698,8 @@ source_set("test_support") {
     "test/test_tile_priorities.h",
     "test/test_web_graphics_context_3d.cc",
     "test/test_web_graphics_context_3d.h",
+    "test/threaded_channel_for_test.cc",
+    "test/threaded_channel_for_test.h",
   ]
 
   configs += [ "//build/config:precompiled_headers" ]