Add a setting to allow window object reuse across a top-level initial navigation.

third_party/WebKit/Source/web/WebSettingsImpl.cpp

Index: third_party/WebKit/Source/web/WebSettingsImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebSettingsImpl.cpp b/third_party/WebKit/Source/web/WebSettingsImpl.cpp
index b464582aeb80c98f96373987a456e50dc2113546..11e8f44fcf40cc8a3ed0d85e4ca2492e552af492 100644
--- a/third_party/WebKit/Source/web/WebSettingsImpl.cpp
+++ b/third_party/WebKit/Source/web/WebSettingsImpl.cpp
@@ -292,6 +292,11 @@ void WebSettingsImpl::setLoadWithOverviewMode(bool enabled)
     m_settings->setLoadWithOverviewMode(enabled);
 }
 
+void WebSettingsImpl::setShouldReuseGlobalForUnownedMainFrame(bool enabled)
+{
+    m_settings->setShouldReuseGlobalForUnownedMainFrame(enabled);
+}
+
 void WebSettingsImpl::setPluginsEnabled(bool enabled)
 {
     m_devToolsEmulator->setPluginsEnabled(enabled);