Set default document urls to 'about:blank'.

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

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index 4b13bb38c904c0136d401125492162169f56e062..57ba4ec2d43e79fbb91df5bdf7f66a76aca1cf3b 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -3303,6 +3303,13 @@ void Document::exceptionThrown(ErrorEvent* event) {
   MainThreadDebugger::instance()->exceptionThrown(this, event);
 }
 
+KURL Document::urlForBinding() {
+  if (!url().isNull()) {
+    return url();
+  }
+  return blankURL();
+}
+
 void Document::setURL(const KURL& url) {
   const KURL& newURL = url.isEmpty() ? blankURL() : url;
   if (newURL == m_url)