[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>
+

[pkotwicz, 2015/01/23 16:00:47]

Nit: No need to include favicon_types.h

[huangs, 2015/01/23 19:47:51]

Need this for favicon_base::FallbackIconStyle , which is a non-pointer member.

+#include "components/favicon_base/favicon_types.h"
+#include "third_party/skia/include/core/SkColor.h"
+
+namespace chrome {
+
+struct ParsedFallbackIconPath {
+  // The URL from which the fallback icon is being requested.

[pkotwicz, 2015/01/23 16:00:47]

How about: "The page URL the fallback icon is requested for."

Your current comment suggests that the URL is the URL of the page requesting the
fallback icon (i.e. the URL of the new tab page)

[huangs, 2015/01/23 19:47:51]

Done.

+  std::string url;
+
+  // The size of the requested fallback icon in pixels.
+  int size_in_pixels;
+
+  // Specifications of fallback icon. This is nullptr if no fallback.

[pkotwicz, 2015/01/23 16:00:47]

Remove the part about the nullptr because it is not true

[huangs, 2015/01/23 19:47:51]

Done.

+  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_