[Icons NTP] Add LargeIconUrlParser.

chrome/common/favicon/large_icon_url_parser.h

Index: chrome/common/favicon/large_icon_url_parser.h
diff --git a/chrome/common/favicon/large_icon_url_parser.h b/chrome/common/favicon/large_icon_url_parser.h
new file mode 100644
index 0000000000000000000000000000000000000000..dd58b8315a589ac47cab694e810577a3652dcc55
--- /dev/null
+++ b/chrome/common/favicon/large_icon_url_parser.h
@@ -0,0 +1,46 @@
+// Copyright 2015 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 CHROME_COMMON_FAVICON_LARGE_ICON_URL_PARSER_H_
+#define CHROME_COMMON_FAVICON_LARGE_ICON_URL_PARSER_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/strings/string_piece.h"
+
+// A parser for parameters to the chrome://large-icon/ host.
+class LargeIconUrlParser {
+ public:
+  LargeIconUrlParser();
+  ~LargeIconUrlParser();
+
+  std::string url_string() const { return url_string_; }
+
+  int size_in_pixels() const { return size_in_pixels_; }
+
+  size_t path_index() const { return path_index_; }
+
+  // Parses |path|, which should be in the format described at the top of the
+  // file "chrome/browser/ui/webui/large_icon_source.h". Note that |path| does
+  // not have leading '/'.
+  bool Parse(base::StringPiece path);
+
+ private:
+  friend class LargeIconUrlParserTest;
+
+  // The page URL string of the requested large icon.
+  std::string url_string_;
+
+  // The size of the requested large icon in pixels.
+  int size_in_pixels_;
+
+  // The index of the first character (relative to the path) where the the URL
+  // from which the large icon is being requested is located.
+  size_t path_index_;
+
+  DISALLOW_COPY_AND_ASSIGN(LargeIconUrlParser);
+};
+
+#endif  // CHROME_COMMON_FAVICON_LARGE_ICON_URL_PARSER_H_