Don't include headers from the layout API from other headers needlessly.

third_party/WebKit/Source/core/frame/RemoteFrame.cpp

 // 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.
 
 #include "core/frame/RemoteFrame.h"
 
 #include "bindings/core/v8/WindowProxy.h"
 #include "bindings/core/v8/WindowProxyManager.h"
 #include "core/dom/RemoteSecurityContext.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/RemoteDOMWindow.h"
 #include "core/frame/RemoteFrameClient.h"
 #include "core/frame/RemoteFrameView.h"
 #include "core/html/HTMLFrameOwnerElement.h"
+#include "core/layout/api/LayoutPartItem.h"
 #include "core/loader/FrameLoadRequest.h"
 #include "core/loader/FrameLoader.h"
 #include "core/paint/PaintLayer.h"
 #include "platform/PluginScriptForbiddenScope.h"
 #include "platform/UserGestureIndicator.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/network/ResourceRequest.h"
 #include "platform/weborigin/SecurityPolicy.h"
 #include "public/platform/WebLayer.h"
 
@@ skipping 176 matching lines @@
     using FrameVector = HeapVector<Member<Frame>>;
     FrameVector childrenToDetach;
     childrenToDetach.reserveCapacity(tree().childCount());
     for (Frame* child = tree().firstChild(); child; child = child->tree().nextSibling())
         childrenToDetach.append(child);
     for (const auto& child : childrenToDetach)
         child->detach(FrameDetachType::Remove);
 }
 
 } // namespace blink