Remove some chrome dependencies from extensions app_window API

extensions/browser/image_util.cc

+// 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.
+
+#include "extensions/browser/image_util.h"
+
+#include <stdint.h>
+#include <vector>
+
+#include "base/strings/string_number_conversions.h"
+#include "third_party/skia/include/core/SkColor.h"
+
+namespace extensions {
+namespace image_util {
+
+bool ParseCSSColorString(const std::string& color_string, SkColor* result) {
+  std::string formatted_color;
+  // Check the string for incorrect formatting.
+  if (color_string.empty() || color_string[0] != '#')
+    return false;
+
+  // Convert the string from #FFF format to #FFFFFF format.
+  if (color_string.length() == 4) {
+    for (size_t i = 1; i < 4; ++i) {
+      formatted_color += color_string[i];
+      formatted_color += color_string[i];
+    }
+  } else if (color_string.length() == 7) {
+    formatted_color = color_string.substr(1, 6);
+  } else {
+    return false;
+  }
+
+  // Convert the string to an integer and make sure it is in the correct value
+  // range.
+  std::vector<uint8_t> color_bytes;
+  if (!base::HexStringToBytes(formatted_color, &color_bytes))
+    return false;
+
+  *result = SkColorSetARGB(255, color_bytes[0], color_bytes[1], color_bytes[2]);
+  return true;
+}
+
+}  // namespace image_util
+}  // namespace extensions