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..47126e9049b0ccb265b258d61c8cf4827705da49 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 baseURL matches with document URL

[fs, 2015/11/20 11:48:36]

Nit: Remove ',', and add '.' at the end. While we're at it: "baseURL matches
with document" -> "the base URL is the same as the document"

+        // This early check fixes the performance regression crbug.com/557979

[fs, 2015/11/20 11:48:36]

Nit: I'd suggest something more like:

"This is a common case, so check that first to avoid resolving the URL (which is
relatively expensive). See crbug.com/..."

+        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());