Allow extensions of the ManifestParser outside of the content/ layer.

content/public/renderer/manifest_parser.h

 // Copyright 2014 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 CONTENT_RENDERER_MANIFEST_MANIFEST_PARSER_H_
-#define CONTENT_RENDERER_MANIFEST_MANIFEST_PARSER_H_
+#ifndef CONTENT_PUBLIC_RENDERER_MANIFEST_PARSER_H_
+#define CONTENT_PUBLIC_RENDERER_MANIFEST_PARSER_H_
 
 #include "base/strings/nullable_string16.h"
 #include "base/strings/string_piece.h"
 #include "content/common/content_export.h"
 #include "content/public/common/manifest.h"
 
 class GURL;
 
 namespace base {
 class DictionaryValue;
 }
 
 namespace content {
 
 // ManifestParser handles the logic of parsing the Web Manifest from a string.
 // It implements:
 // http://w3c.github.io/manifest/#dfn-steps-for-processing-a-manifest
 class CONTENT_EXPORT ManifestParser {
  public:
-  ManifestParser(const base::StringPiece& data,
-                 const GURL& manifest_url,
-                 const GURL& document_url);
-  ~ManifestParser();
+  // Returns an implementation of the ManifestParser.
+  static scoped_ptr<ManifestParser> Get();
+  virtual ~ManifestParser();
 
   // Parse the Manifest from a string using following:
   // http://w3c.github.io/manifest/#dfn-steps-for-processing-a-manifest
-  void Parse();
+  void Parse(const base::StringPiece& data,
+             const GURL& manifest_url,
+             const GURL& document_url);
 
   const Manifest& manifest() const;
   const std::vector<std::string>& errors() const;
   bool failed() const;
 
- private:
+ protected:
   // Used to indicate whether to strip whitespace when parsing a string.
   enum TrimType {
     Trim,
     NoTrim
   };
 
+  // It is not possible to create a direct instance of the ManifestParser to
+  // allow it to be overridden with ContentRendererClient.

[Avi (use Gerrit), 2015/02/20 20:07:57]

I can't parse this sentence. Rather than "it is not possible" say "disallow" if
that's what you mean.

And what's going on here? How does not allowing a direct instantiation interact
with the ContentRendererClient?

+  ManifestParser();
+
+  // Parses extensions of the ManifestParser. This is expected to be implemented
+  // by objects returned from ContentRendererClient::OverrideManifestParser().
+  // That call happens before the regular parsing of the Manifest to prevent
+  // manifest parsing extensions to override regular parsing.
+  // https://w3c.github.io/manifest/#dfn-extension-point
+  virtual void ParseExtensionPoint(const base::DictionaryValue& dictionary);
+
   // Helper function to parse booleans present on a given |dictionary| in a
   // given field identified by its |key|.
   // Returns the parsed boolean if any, or |default_value| if parsing failed.
   bool ParseBoolean(const base::DictionaryValue& dictionary,
                     const std::string& key,
                     bool default_value);
 
   // Helper function to parse strings present on a given |dictionary| in a given
   // field identified by its |key|.
   // Returns the parsed string if any, a null string if the parsing failed.
@@ skipping 61 matching lines @@
   // by gfx::Size(0, 0).
   std::vector<gfx::Size> ParseIconSizes(const base::DictionaryValue& icon);
 
   // Parses the 'icons' field of a Manifest, as defined in:
   // http://w3c.github.io/manifest/#dfn-steps-for-processing-the-icons-member
   // Returns a vector of Manifest::Icon with the successfully parsed icons, if
   // any. An empty vector if the field was not present or empty.
   std::vector<Manifest::Icon> ParseIcons(
       const base::DictionaryValue& dictionary);
 
-  // Parses the 'gcm_sender_id' field of the manifest.
-  // This is a proprietary extension of the Web Manifest specification.
-  // Returns the parsed string if any, a null string if the parsing failed.
-  base::NullableString16 ParseGCMSenderID(
-      const base::DictionaryValue& dictionary);
-
-  // Parses the 'gcm_user_visible_only' field of the manifest.
-  // This is a proprietary extension of the Web Manifest specification.
-  // Returns true iff the string could be parsed as the boolean true.
-  bool ParseGCMUserVisibleOnly(const base::DictionaryValue& dictionary);
-
-  const base::StringPiece& data_;
   GURL manifest_url_;
   GURL document_url_;
 
   bool failed_;
   Manifest manifest_;
   std::vector<std::string> errors_;
 
+ private:
   DISALLOW_COPY_AND_ASSIGN(ManifestParser);
 };
 
 } // namespace content
 
-#endif // CONTENT_RENDERER_MANIFEST_MANIFEST_PARSER_H_
+#endif // CONTENT_PUBLIC_RENDERER_MANIFEST_PARSER_H_