Add url::Origin::GetURL() to convert Origins to URLs without reparsing

url/origin.cc

Index: url/origin.cc
diff --git a/url/origin.cc b/url/origin.cc
index a14c8918d35bfbf4430d0d5c5d7ebee577639f95..68f978e8fd640025eb161aca57b6d83fda64fe23 100644
--- a/url/origin.cc
+++ b/url/origin.cc
@@ -17,6 +17,12 @@
 
 namespace url {
 
+namespace {
+
+const char kRootFileUrl[] = "file:///";
+
+}  // namespace
+
 Origin::Origin() : unique_(true) {
 }
 
@@ -60,11 +66,21 @@ std::string Origin::Serialize() const {
     return "null";
 
   if (scheme() == kFileScheme)
-    return "file://";
+    return kRootFileUrl;

[brettw, 2016/10/03 18:56:34]

It looks like this returns the new "file:///" instead which doesn't match what
you said in the last review comment. (If these two cases have to be different,
the constant at the top probably isn't helping).

Assumeing they should be different, it's probably a good idea to call out in
comments here in the implementation why (even though we're adding something to
the header) so somebody doesn't try to "fix" it later.

 
   return tuple_.Serialize();
 }
 
+GURL Origin::GetURL() const {
+  if (unique())
+    return GURL();
+
+  if (scheme() == kFileScheme)
+    return GURL(kRootFileUrl);
+
+  return tuple_.GetURL();
+}
+
 bool Origin::IsSameOriginWith(const Origin& other) const {
   if (unique_ || other.unique_)
     return false;