[Favicon] Add new fallback icon rendering flow.

chrome/common/favicon/fallback_icon_url_parser.h

+// 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_FALLBACK_ICON_URL_PARSER_H_
+#define CHROME_COMMON_FAVICON_FALLBACK_ICON_URL_PARSER_H_
+
+#include <string>
+
+#include "components/favicon_base/favicon_types.h"
+#include "third_party/skia/include/core/SkColor.h"
+
+namespace chrome {
+
+struct ParsedFallbackIconPath {
+  // The page URL the fallback icon is requested for.
+  std::string url;
+
+  // The size of the requested fallback icon in pixels.
+  int size_in_pixels;
+
+  // Styling specifications of fallback icon.
+  favicon_base::FallbackIconStyle style;
+};
+
+// Parses a color in "RGB", "RRGGBB", or "RRGGBBAA" format. Returns true on
+// success.
+bool ParseIconColor(const std::string& str, SkColor* color);
+
+
+// Parses |specs_str|, which should be the comma-separated value portion
+// in the format described at the top of the file
+// "chrome/browser/ui/webui/fallback_icon_source.h".
+bool ParseFallbackIconSpecs(const std::string& specs_str,
+                            int *size,
+                            favicon_base::FallbackIconStyle* style);
+
+// Parses |path|, which should be in the format described at the top of the
+// file "chrome/browser/ui/webui/fallback_icon_source.h".
+bool ParseFallbackIconPath(const std::string& path,
+                           ParsedFallbackIconPath* parsed);
+
+}  // namespace chrome
+
+#endif  // CHROME_COMMON_FAVICON_FALLBACK_ICON_URL_PARSER_H_