Make inSameLine() in VisibleUnits.cpp to work with positions in composed tree

Source/core/editing/EditingTestBase.cpp

Index: Source/core/editing/EditingTestBase.cpp
diff --git a/Source/core/editing/EditingTestBase.cpp b/Source/core/editing/EditingTestBase.cpp
index d22b8d7e0fb046feb7439be5d14418472fa7a593..f437d241b9198e4e4bfe8f7630dab41b2deeea6d 100644
--- a/Source/core/editing/EditingTestBase.cpp
+++ b/Source/core/editing/EditingTestBase.cpp
@@ -8,6 +8,7 @@
 #include "core/dom/Document.h"
 #include "core/dom/Range.h"
 #include "core/dom/Text.h"
+#include "core/frame/FrameView.h"
 #include "core/html/HTMLElement.h"
 #include "core/testing/DummyPageHolder.h"
 
@@ -48,6 +49,11 @@ PassRefPtrWillBeRawPtr<ShadowRoot> EditingTestBase::setShadowContent(const char*
     return createShadowRootForElementWithIDAndSetInnerHTML(document(), "host", shadowContent);
 }
 
+void EditingTestBase::updateLayoutAndStyleForPainting()
+{
+    document().view()->updateLayoutAndStyleForPainting();
+}
+
 Position EditingTestBase::positionInDOMTree(Node& anchor, int offset)
 {
     return Position(&anchor, offset, Position::PositionIsOffsetInAnchor);