Fix for perf Regression in SVG with Fragment URIs

third_party/WebKit/Source/core/svg/SVGURIReference.h

Index: third_party/WebKit/Source/core/svg/SVGURIReference.h
diff --git a/third_party/WebKit/Source/core/svg/SVGURIReference.h b/third_party/WebKit/Source/core/svg/SVGURIReference.h
index 7174a3b6b4d5b3ebc82767ccaa7d095c09751271..b676bd33a1b6a394bf5786108b4f210598539907 100644
--- a/third_party/WebKit/Source/core/svg/SVGURIReference.h
+++ b/third_party/WebKit/Source/core/svg/SVGURIReference.h
@@ -41,6 +41,11 @@ public:
 
     static inline bool isExternalURIReference(const String& uri, const Document& document)
     {
+        // Fragment-only URIs are always internal if the baseURL is same as the document URL.
+        // This is common case, so check that first to avoid resolving URL (which is relatively expensive). See crbug.com/557979
+        if (document.baseURL() == document.url() && uri.startsWith('#'))
+            return false;
+
         // If the URI matches our documents URL, we're dealing with a local reference.
         KURL url = document.completeURL(uri);
         return !equalIgnoringFragmentIdentifier(url, document.url());