Retry to add MockPresentationClient to use in layout tests.

content/shell/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")
 import("//build/config/ui.gni")
 import("//tools/grit/repack.gni")
 import("//tools/grit/grit_rule.gni")
 if (is_android) {
   import("//build/config/android/config.gni")
@@ skipping 154 matching lines @@
     "renderer/test_runner/gamepad_controller.cc",
     "renderer/test_runner/gamepad_controller.h",
     "renderer/test_runner/mock_color_chooser.cc",
     "renderer/test_runner/mock_color_chooser.h",
     "renderer/test_runner/mock_constraints.cc",
     "renderer/test_runner/mock_constraints.h",
     "renderer/test_runner/mock_credential_manager_client.cc",
     "renderer/test_runner/mock_credential_manager_client.h",
     "renderer/test_runner/mock_grammar_check.cc",
     "renderer/test_runner/mock_grammar_check.h",
+    "renderer/test_runner/mock_presentation_client.cc",
+    "renderer/test_runner/mock_presentation_client.h",
     "renderer/test_runner/mock_screen_orientation_client.cc",
     "renderer/test_runner/mock_screen_orientation_client.h",
     "renderer/test_runner/mock_spell_check.cc",
     "renderer/test_runner/mock_spell_check.h",
     "renderer/test_runner/mock_web_audio_device.cc",
     "renderer/test_runner/mock_web_audio_device.h",
     "renderer/test_runner/mock_web_media_stream_center.cc",
     "renderer/test_runner/mock_web_media_stream_center.h",
     "renderer/test_runner/mock_web_midi_accessor.cc",
     "renderer/test_runner/mock_web_midi_accessor.h",
@@ skipping 333 matching lines @@
       # image diff rather than having content shell depend on it.
       datadeps = [
         "//tools/imagediff($host_toolchain)",
       ]
     }
   }
 } else {
   group("content_shell") {
   }
 }