Dynamically inserted StyleSheet shouldn't block loading.

third_party/WebKit/Source/core/html/HTMLLinkElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLLinkElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLLinkElement.cpp b/third_party/WebKit/Source/core/html/HTMLLinkElement.cpp
index e18c443f1caca3a6d4529b352760b7b0e6e79e76..e3a6738e2536ffc254d596c93311a6349e4b3fa1 100644
--- a/third_party/WebKit/Source/core/html/HTMLLinkElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLLinkElement.cpp
@@ -725,7 +725,7 @@ void LinkStyle::process()
 
         // Don't hold up layout tree construction and script execution on stylesheets
         // that are not needed for the layout at the moment.
-        bool blocking = mediaQueryMatches && !m_owner->isAlternate();
+        bool blocking = mediaQueryMatches && !m_owner->isAlternate() && m_owner->isCreatedByParser();
         addPendingSheet(blocking ? Blocking : NonBlocking);
 
         // Load stylesheets that are not needed for the layout immediately with low priority.