Fix preloadScanner double download issue with link preload and media

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

Index: third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.cpp
diff --git a/third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.cpp b/third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.cpp
index 01b52462b2cb4fdd8fa468a035ef476442b0cea4..1cb0661a96c90c95802fd19a4180b38e8fa0b607 100644
--- a/third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.cpp
+++ b/third_party/WebKit/Source/core/html/parser/HTMLPreloadScanner.cpp
@@ -205,12 +205,15 @@ public:
     PassOwnPtr<PreloadRequest> createPreloadRequest(const KURL& predictedBaseURL, const SegmentedString& source, const ClientHintsPreferences& clientHintsPreferences, const PictureData& pictureData, const ReferrerPolicy documentReferrerPolicy)
     {
         PreloadRequest::RequestType requestType = PreloadRequest::RequestTypePreload;
-        if (shouldPreconnect())
+        if (shouldPreconnect()) {
             requestType = PreloadRequest::RequestTypePreconnect;
-        else if (isLinkRelPreload())
-            requestType = PreloadRequest::RequestTypeLinkRelPreload;
-        else if (!shouldPreload() || !m_matchedMediaAttribute)
+        } else if (!shouldPreload() || !m_matchedMediaAttribute) {
             return nullptr;
+        }
+
+        if (isLinkRelPreload()) {

[Nate Chapin, 2016/05/17 17:16:55]

Which of these cases really should be mutually exclusive? It seems suspicious
that this patch makes preload and preconnect not mutually exclusive.

[Yoav Weiss, 2016/05/17 21:45:48]

Good point. I changed the conditions to represent the fact that preconnect is
mutual exclusive with link preload as well as regular preload checks.

+            requestType = PreloadRequest::RequestTypeLinkRelPreload;
+        }
 
         TextPosition position = TextPosition(source.currentLine(), source.currentColumn());
         FetchRequest::ResourceWidth resourceWidth;