Revert changes to GPU test MessageLoop type.

gpu/BUILD.gn

Index: gpu/BUILD.gn
diff --git a/gpu/BUILD.gn b/gpu/BUILD.gn
index d726a637fd69b4234ea3c1489c8ddaac69a65ec8..92f136e57fe87643f538e742a6c0e3f1fa8f24ee 100644
--- a/gpu/BUILD.gn
+++ b/gpu/BUILD.gn
@@ -110,7 +110,6 @@ static_library("test_support") {
     "command_buffer/service/error_state_mock.h",
     "command_buffer/service/gles2_cmd_decoder_mock.cc",
     "command_buffer/service/gles2_cmd_decoder_mock.h",
-    "test_message_loop_type.h",
   ]
 
   public_deps = [
@@ -122,9 +121,6 @@ static_library("test_support") {
     "//testing/gtest",
     "//ui/gl:gl_unittest_utils",
   ]
-  if (use_ozone) {
-    deps += [ "//ui/ozone" ]
-  }
 }
 
 test("gl_tests") {