Fix AXLayoutObject not to add duplicated children for CSS first-letter

third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp

Index: third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp
diff --git a/third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp b/third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp
index 617e4aa073d2c1297a17e637871cd45cac1a592b..eef1ab9155016de6964f5f42b110a52dfede5086 100644
--- a/third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp
+++ b/third_party/WebKit/Source/modules/accessibility/AXLayoutObject.cpp
@@ -67,6 +67,7 @@
 #include "core/layout/LayoutListMarker.h"
 #include "core/layout/LayoutMenuList.h"
 #include "core/layout/LayoutTextControl.h"
+#include "core/layout/LayoutTextFragment.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/api/LayoutAPIShim.h"
 #include "core/layout/api/LayoutViewItem.h"
@@ -126,6 +127,13 @@ static inline LayoutObject* firstChildConsideringContinuation(
     LayoutObject* layoutObject) {
   LayoutObject* firstChild = layoutObject->slowFirstChild();
 
+  // CSS first-letter pseudo element is handled as continuation. Returning it
+  // will result in duplicated elements.
+  if (firstChild && firstChild->isText() &&
+      toLayoutText(firstChild)->isTextFragment() &&
+      toLayoutTextFragment(firstChild)->firstLetterPseudoElement())
+    return nullptr;
+
   if (!firstChild && isInlineWithContinuation(layoutObject))
     firstChild = firstChildInContinuation(toLayoutInline(*layoutObject));