Introduce RenderingTest::getLayoutObjectByElementId().

third_party/WebKit/Source/core/layout/LayoutTestHelper.h

 // 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.
 
 #ifndef LayoutTestHelper_h
 #define LayoutTestHelper_h
 
 #include "core/dom/Document.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
@@ skipping 32 matching lines @@
 
     // Both enables compositing and runs the document lifecycle.
     void enableCompositing()
     {
         m_pageHolder->page().settings().setAcceleratedCompositingEnabled(true);
         document().view()->setParentVisible(true);
         document().view()->setSelfVisible(true);
         document().view()->updateAllLifecyclePhases();
     }
 
+    LayoutObject* getLayoutObjectByElementId(const char* id) const
+    {
+        Node* node = document().getElementById(id);
+        return node ? node->layoutObject() : nullptr;
+    }
+
 private:
     RefPtrWillBePersistent<LocalFrame> m_subframe;
     OwnPtrWillBePersistent<FrameLoaderClient> m_frameLoaderClient;
     OwnPtr<DummyPageHolder> m_pageHolder;
 };
 
 class SingleChildFrameLoaderClient final : public EmptyFrameLoaderClient {
 public:
     static PassOwnPtrWillBeRawPtr<SingleChildFrameLoaderClient> create() { return adoptPtrWillBeNoop(new SingleChildFrameLoaderClient); }
 
@@ skipping 31 matching lines @@
 
 private:
     explicit FrameLoaderClientWithParent(Frame* parent) : m_parent(parent) { }
 
     RefPtrWillBeMember<Frame> m_parent;
 };
 
 } // namespace blink
 
 #endif // LayoutTestHelper_h