Implement URL and Origin typemaps/struct traits for blink.

third_party/WebKit/Source/platform/mojo/KURLStructTraits.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef KURLStructTraits_h
+#define KURLStructTraits_h
+
+#include "platform/weborigin/KURL.h"
+#include "url/mojo/url.mojom-blink.h"
+#include "url/url_constants.h"
+
+namespace mojo {
+
+template <>
+struct StructTraits<url::mojom::blink::Url, ::blink::KURL> {
+    static WTF::String url(const ::blink::KURL& r)

[esprehn, 2016/05/25 17:06:27]

what calls this? Nothing in this file seems to use it. This matches some
variable defined in the mojom? Which one?

Also don't abbreviate in blink. what is |r| ? 

[Marijn Kruisselbrink, 2016/05/25 17:35:08]

This matches the "url" field in the url.mojom.Url struct. StructTraits are
documented at
https://www.chromium.org/developers/design-documents/mojo/type-mapping#TOC-St...
renamed it to |blinkUrl|.

+    {
+        if (!r.isValid() || r.getString().length() > url::kMaxURLChars) {
+            return emptyString();
+        }
+
+        return r.getString();
+    }
+    static bool Read(url::mojom::blink::UrlDataView data, ::blink::KURL* out)
+    {
+        WTF::String urlString;
+        if (!data.ReadUrl(&urlString))
+            return false;
+
+        if (urlString.length() > url::kMaxURLChars)
+            return false;
+
+        *out = ::blink::KURL(::blink::KURL(), urlString);
+        if (!urlString.isEmpty() && !out->isValid())
+            return false;
+
+        return true;
+    }
+};
+}
+
+#endif // KURLStructTraits_h