Check whether a text node may be about to be redistributed in ShouldUpdateLayoutByReattaching()

third_party/WebKit/Source/core/dom/Text.cpp

Index: third_party/WebKit/Source/core/dom/Text.cpp
diff --git a/third_party/WebKit/Source/core/dom/Text.cpp b/third_party/WebKit/Source/core/dom/Text.cpp
index bd379c0c31be77a9f5e36af4496144316a5733ef..dabcd84b6ff54cc7361be8949de10c2d76603d58 100644
--- a/third_party/WebKit/Source/core/dom/Text.cpp
+++ b/third_party/WebKit/Source/core/dom/Text.cpp
@@ -31,6 +31,7 @@
 #include "core/dom/LayoutTreeBuilderTraversal.h"
 #include "core/dom/NodeComputedStyle.h"
 #include "core/dom/NodeTraversal.h"
+#include "core/dom/shadow/ElementShadow.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/events/ScopedEventQueue.h"
 #include "core/layout/LayoutText.h"
@@ -446,6 +447,11 @@ static bool ShouldUpdateLayoutByReattaching(const Text& text_node,
                                           *text_layout_object->Parent())) {
     return true;
   }
+  // Check whether this node may be about to be redistributed.
+  if (text_node.ParentElementShadow() &&

[yosin_UTC9, 2017/06/02 07:47:43]

What is happend when Text is descendant of shadow host? 

e.g.
<div id="shadowHost"><span>My parent is not shadow host</span></div>

+      text_node.ParentElementShadow()->NeedsDistributionRecalc()) {
+    return true;
+  }
   if (text_layout_object->IsTextFragment()) {
     // Changes of |textNode| may change first letter part, so we should
     // reattach.