Remove some chrome dependencies from extensions app_window API

extensions/browser/image_util.h

+// 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.
+
+#ifndef EXTENSIONS_BROWSER_IMAGE_UTIL_H_

[James Cook, 2014/04/02 20:15:47]

This file is called image_util.h instead of color_util.h because I anticipate
more image-related utility functions (for window icons, extension icons, etc.)
to move here soon.

+#define EXTENSIONS_BROWSER_IMAGE_UTIL_H_
+
+#include <string>
+
+typedef unsigned int SkColor;
+
+// This file contains various utility functions for extension images and colors.
+namespace extensions {
+namespace image_util {
+
+// Parses a string like #FF9982 or #EEE to a color. Returns true for success.
+bool ParseCSSColorString(const std::string& color_string, SkColor* result);
+
+}  // namespace image_util
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_IMAGE_UTIL_H__