Extend components/test_runner's generated WebMediaStream to have a ChromeMock VideoTrack and Source

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 75 matching lines @@
 
   # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
   deps = [
     ":resources",
     "//base:base",
     "//base:i18n",
     "//cc",
     "//cc/blink",
+    "//components/test_runner/renderer",
     "//gin",
     "//gpu",
     "//net",
     "//skia",
     "//third_party/WebKit/public:blink",
     "//ui/events:dom_keycode_converter",
     "//ui/events:events_base",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//url",
@@ skipping 76 matching lines @@
 
     if (is_mac) {
       libs = [ "AppKit.framework" ]
     }
 
     deps = [
       "//build/config/sanitizers:deps",
     ]
   }
 }