[Icons NTP] Add LargeIconUrlParser.

chrome/common/favicon/large_icon_url_parser.cc

+// 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.
+
+#include "chrome/common/favicon/large_icon_url_parser.h"
+
+#include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
+#include "third_party/skia/include/utils/SkParse.h"
+#include "ui/gfx/favicon_size.h"
+
+namespace chrome {
+
+LargeIconUrlParser::LargeIconUrlParser() : size_in_pixels_(48) {
+}
+
+LargeIconUrlParser::~LargeIconUrlParser() {
+}
+
+bool LargeIconUrlParser::Parse(base::StringPiece path) {
+  if (path.empty())
+    return false;
+
+  size_t slash = path.find("/", 0);  // |path| does not start with '/'.
+  if (slash == base::StringPiece::npos)
+    return false;
+  base::StringPiece size_str = path.substr(0, slash);
+  // Disallow empty, non-numeric, or negative sizes.
+  if (size_str.empty() ||
+      !base::StringToInt(size_str, &size_in_pixels_) ||
+      size_in_pixels_ <= 0)
+    return false;
+
+  // Need to store the index of the URL field, so Instant Extended can translate
+  // large icon URLs using advanced parameters.
+  // Example:
+  //   "chrome-search://large-icon/48/<renderer-id>/<most-visited-id>"
+  // would be translated to:
+  //   "chrome-search://large-icon/48/<most-visited-item-with-given-id>".
+  path_index_ = slash + 1;
+  url_string_ = path.substr(path_index_).as_string();
+  return true;
+}
+
+}  // namespace chrome