Revert of Remove MockConstraints

components/test_runner/BUILD.gn

 # Copyright 2015 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")
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
@@ skipping 13 matching lines @@
     "blink_test_platform_support_mac.mm",
     "blink_test_platform_support_win.cc",
     "event_sender.cc",
     "event_sender.h",
     "gamepad_controller.cc",
     "gamepad_controller.h",
     "gc_controller.cc",
     "gc_controller.h",
     "mock_color_chooser.cc",
     "mock_color_chooser.h",
+    "mock_constraints.cc",
+    "mock_constraints.h",
     "mock_credential_manager_client.cc",
     "mock_credential_manager_client.h",
     "mock_grammar_check.cc",
     "mock_grammar_check.h",
     "mock_screen_orientation_client.cc",
     "mock_screen_orientation_client.h",
     "mock_spell_check.cc",
     "mock_spell_check.h",
     "mock_web_audio_device.cc",
     "mock_web_audio_device.h",
@@ skipping 144 matching lines @@
 
     if (is_mac) {
       libs = [ "AppKit.framework" ]
     }
 
     deps = [
       "//build/config/sanitizers:deps",
     ]
   }
 }