Preload scan external css for @import

third_party/WebKit/Source/core/fetch/CSSStyleSheetResource.cpp

Index: third_party/WebKit/Source/core/fetch/CSSStyleSheetResource.cpp
diff --git a/third_party/WebKit/Source/core/fetch/CSSStyleSheetResource.cpp b/third_party/WebKit/Source/core/fetch/CSSStyleSheetResource.cpp
index 8aa33d13f76e3b233933654410925106089ba313..78ebcd9928613cb4efdb798cef7753d0910e510b 100644
--- a/third_party/WebKit/Source/core/fetch/CSSStyleSheetResource.cpp
+++ b/third_party/WebKit/Source/core/fetch/CSSStyleSheetResource.cpp
@@ -51,6 +51,7 @@ CSSStyleSheetResource* CSSStyleSheetResource::createForTest(const ResourceReques
 
 CSSStyleSheetResource::CSSStyleSheetResource(const ResourceRequest& resourceRequest, const ResourceLoaderOptions& options, const String& charset)
     : StyleSheetResource(resourceRequest, CSSStyleSheet, options, "text/css", charset)
+    , m_didNotifyFirstData(false)
 {
 }
 
@@ -98,6 +99,17 @@ const String CSSStyleSheetResource::sheetText(MIMETypeCheck mimeTypeCheck) const
     return decodedText();
 }
 
+void CSSStyleSheetResource::appendData(const char* data, size_t length)
+{
+    Resource::appendData(data, length);
+    if (m_didNotifyFirstData)
+        return;
+    ResourceClientWalker<StyleSheetResourceClient> w(m_clients);
+    while (StyleSheetResourceClient* c = w.next())
+        c->didAppendFirstData(this);
+    m_didNotifyFirstData = true;
+}
+
 void CSSStyleSheetResource::checkNotify()
 {
     // Decode the data to find out the encoding and keep the sheet text around during checkNotify()