Removed superfluous custom style DCHECK.

third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp

Index: third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp
diff --git a/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp b/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp
index 01cd41d69c3b54885f77aed9b77982d2fde82627..275f234b159e40d1e20d1d28f2d74f9b45e975ec 100644
--- a/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp
+++ b/third_party/WebKit/Source/core/dom/shadow/ShadowRoot.cpp
@@ -158,9 +158,6 @@ void ShadowRoot::RecalcStyle(StyleRecalcChange change) {
 }
 
 void ShadowRoot::RebuildLayoutTree(Text*& next_text_sibling) {
-  // ShadowRoot doesn't support custom callbacks.
-  DCHECK(!HasCustomStyleCallbacks());
-
   if (!NeedsReattachLayoutTree() && !ChildNeedsReattachLayoutTree()) {
     SkipRebuildLayoutTree(next_text_sibling);
     return;