Do not sanitize about:blank/#foo & about:blank?foo

url/url_util.cc

Index: url/url_util.cc
diff --git a/url/url_util.cc b/url/url_util.cc
index 2c8d6978cb72c5c7665135bcd9d7a36e7941be77..9a2cce47aa116c047e8d49cc6235941be944075d 100644
--- a/url/url_util.cc
+++ b/url/url_util.cc
@@ -10,6 +10,7 @@
 #include "base/debug/leak_annotations.h"
 #include "base/logging.h"
 #include "base/strings/string_util.h"
+#include "url/gurl.h"
 #include "url/url_canon_internal.h"
 #include "url/url_constants.h"
 #include "url/url_file.h"
@@ -608,6 +609,21 @@ bool IsReferrerScheme(const char* spec, const Component& scheme) {
   return DoIsInSchemes(spec, scheme, &unused_scheme_type, *referrer_schemes);
 }
 
+bool IsAboutBlank(const GURL& url) {
+  if (!url.SchemeIs(url::kAboutScheme))
+    return false;
+
+  if (url.has_host() || url.has_username() || url.has_password() ||
+      url.has_port()) {
+    return false;
+  }
+
+  if (url.path() != kAboutBlankPath && url.path() != kAboutBlankWithHashPath)
+    return false;
+
+  return true;
+}
+
 bool FindAndCompareScheme(const char* str,
                           int str_len,
                           const char* compare,