Add support for 'start_url' in Manifest.

content/renderer/manifest/manifest_parser.h

Index: content/renderer/manifest/manifest_parser.h
diff --git a/content/renderer/manifest/manifest_parser.h b/content/renderer/manifest/manifest_parser.h
index 8d49b9885ae0c109d75b414639b8f7a5ae285d22..488127953081448faf7689810918014394f26c36 100644
--- a/content/renderer/manifest/manifest_parser.h
+++ b/content/renderer/manifest/manifest_parser.h
@@ -8,6 +8,8 @@
 #include "base/strings/string_piece.h"
 #include "content/common/content_export.h"
 
+class GURL;
+
 namespace base {
 class DictionaryValue;
 }
@@ -21,7 +23,9 @@ struct Manifest;
 // http://w3c.github.io/manifest/#dfn-steps-for-processing-a-manifest
 class CONTENT_EXPORT ManifestParser {
  public:
-  static Manifest Parse(const base::StringPiece&);
+  static Manifest Parse(const base::StringPiece&,
+                        const GURL& manifest_url,
+                        const GURL& document_url);
 };
 
 } // namespace content