Use mojo from the PDF extension instead of using an extension API.

extensions/renderer/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/features.gni")
 
 assert(enable_extensions)
 
 source_set("renderer") {
   sources = [
@@ skipping 232 matching lines @@
       "//third_party/openh264:encoder",
       "//third_party/wds:libwds",
     ]
   }
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "activity_log_converter_strategy_unittest.cc",
-    "api/mojo_private/mojo_private_unittest.cc",
-    "api_test_base.cc",
-    "api_test_base.h",
-    "api_test_base_unittest.cc",
     "event_unittest.cc",
     "gc_callback_unittest.cc",
     "json_schema_unittest.cc",
     "messaging_utils_unittest.cc",
     "module_system_test.cc",
     "module_system_test.h",
     "module_system_unittest.cc",
-    "mojo/keep_alive_client_unittest.cc",
     "safe_builtins_unittest.cc",
     "scoped_web_frame.cc",
     "scoped_web_frame.h",
     "script_context_set_unittest.cc",
     "script_context_unittest.cc",
     "utils_unittest.cc",
   ]
 
   deps = [
     ":renderer",
@@ skipping 10 matching lines @@
     "//ui/base",
   ]
 
   if (enable_wifi_display && proprietary_codecs) {
     sources += [
       "api/display_source/wifi_display/wifi_display_elementary_stream_descriptor_unittest.cc",
       "api/display_source/wifi_display/wifi_display_media_packetizer_unittest.cc",
     ]
   }
 }