Prefetch @import files from CSS files.

Source/core/fetch/CSSStyleSheetResource.cpp

Index: Source/core/fetch/CSSStyleSheetResource.cpp
diff --git a/Source/core/fetch/CSSStyleSheetResource.cpp b/Source/core/fetch/CSSStyleSheetResource.cpp
index 38dffed655f0f3b8975f979f5bb868bb7c97e4e7..973f44f01d77dc33cd1501b2021ee54267daf317 100644
--- a/Source/core/fetch/CSSStyleSheetResource.cpp
+++ b/Source/core/fetch/CSSStyleSheetResource.cpp
@@ -108,6 +108,16 @@ void CSSStyleSheetResource::checkNotify()
     m_decodedSheetText = String();
 }
 
+void CSSStyleSheetResource::appendData(const char* data, int length)
+{
+    Resource::appendData(data, length);
+
+    ResourcePtr<CSSStyleSheetResource> protect(this);
+    ResourceClientWalker<StyleSheetResourceClient> w(m_clients);
+    while (StyleSheetResourceClient* c = w.next())
+        c->dataReceived(this, data, length);
+}
+
 bool CSSStyleSheetResource::isSafeToUnlock() const
 {
     return m_parsedStyleSheetCache;