Preload scan external css for @import

third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.cpp

Index: third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.cpp
diff --git a/third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.cpp b/third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.cpp
index 15a5aaf1d36714052c7ccaf8db2548737a75454c..78d76e8b88219bc5fe685357144cbcb61f38ac99 100644
--- a/third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.cpp
+++ b/third_party/WebKit/Source/core/html/parser/CSSPreloadScanner.cpp
@@ -27,8 +27,10 @@
 
 #include "core/html/parser/CSSPreloadScanner.h"
 
+#include "core/fetch/CSSStyleSheetResource.h"
 #include "core/fetch/FetchInitiatorTypeNames.h"
 #include "core/html/parser/HTMLParserIdioms.h"
+#include "core/html/parser/HTMLResourcePreloader.h"
 #include "platform/text/SegmentedString.h"
 
 namespace blink {
@@ -233,4 +235,25 @@ void CSSPreloadScanner::emitRule(const SegmentedString& source)
     m_ruleValue.clear();
 }
 
+CSSPreloaderResourceClient::CSSPreloaderResourceClient(HTMLResourcePreloader* preloader)
+    : m_preloader(preloader)
+    , m_streamPosition(0)
+{
+}
+
+void CSSPreloaderResourceClient::didAppendData(const CSSStyleSheetResource* resource)
+{
+    preloadChunk(resource->streamDecodedText(&m_streamPosition), resource);
+}
+
+void CSSPreloaderResourceClient::preloadChunk(const String& chunk, const CSSStyleSheetResource* resource)
+{
+    if (chunk.isNull())
+        return;
+    PreloadRequestStream preloads;
+    // TODO(csharrison): Should SegmentedString be populated?
+    m_cssPreloadScanner.scan(chunk, SegmentedString(), preloads, resource->response().url());
+    m_preloader->takeAndPreload(preloads);
+}
+
 } // namespace blink