Mojo C++ bindings: switch the existing usage of StructTraits to use the new data view interface.

url/mojo/url_gurl_struct_traits.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 URL_MOJO_URL_GURL_STRUCT_TRAITS_H_
 #define URL_MOJO_URL_GURL_STRUCT_TRAITS_H_
 
 #include "base/strings/string_piece.h"
 #include "url/gurl.h"
 #include "url/mojo/url.mojom.h"
 #include "url/url_constants.h"
 
 namespace mojo {
 
 template <>
 struct StructTraits<url::mojom::Url, GURL> {
   static base::StringPiece url(const GURL& r) {
     if (r.possibly_invalid_spec().length() > url::kMaxURLChars ||
         !r.is_valid()) {
       return base::StringPiece();
     }
 
     return base::StringPiece(r.possibly_invalid_spec().c_str(),
                              r.possibly_invalid_spec().length());
   }
-  static bool Read(url::mojom::Url::Reader r, GURL* out) {
-    if (r.url().length() > url::kMaxURLChars) {
-      *out = GURL();
+  static bool Read(url::mojom::UrlDataView data, GURL* out) {
+    base::StringPiece url_string;
+    if (!data.ReadUrl(&url_string))
       return false;
-    }
-    *out = GURL(r.url());
-    if (!r.url().empty() && !out->is_valid()) {
-      *out = GURL();
+
+    if (url_string.length() > url::kMaxURLChars)
       return false;
-    }
+
+    *out = GURL(url_string);
+    if (!url_string.empty() && !out->is_valid())
+      return false;
+
     return true;
   }
 };
 
 }
 
 #endif  // URL_MOJO_URL_GURL_STRUCT_TRAITS_H_