Blink Plugins: Remove Shadow DOM Plugin Placeholder remnants.

Source/core/testing/Internals.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 102 matching lines @@
 #include "core/page/Page.h"
 #include "core/page/PrintContext.h"
 #include "core/paint/DeprecatedPaintLayer.h"
 #include "core/svg/SVGImageElement.h"
 #include "core/testing/DictionaryTest.h"
 #include "core/testing/GCObservation.h"
 #include "core/testing/InternalRuntimeFlags.h"
 #include "core/testing/InternalSettings.h"
 #include "core/testing/LayerRect.h"
 #include "core/testing/LayerRectList.h"
-#include "core/testing/PluginPlaceholderOptions.h"
 #include "core/testing/PrivateScriptTest.h"
 #include "core/testing/TypeConversions.h"
 #include "core/testing/UnionTypesTest.h"
 #include "core/workers/WorkerThread.h"
 #include "platform/Cursor.h"
 #include "platform/Language.h"
 #include "platform/PlatformKeyboardEvent.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/TraceEvent.h"
 #include "platform/geometry/IntRect.h"
@@ skipping 2346 matching lines @@
 
     return animator->setScrollbarsVisibleForTesting(visible);
 }
 
 void Internals::forceRestrictIFramePermissions()
 {
     RuntimeEnabledFeatures::setRestrictIFramePermissionsEnabled(true);
 }
 
 } // namespace blink