[devtools] Support different encodings for Page.CaptureScreenshot.

content/browser/devtools/protocol/page_handler_image_utils.h

+// Copyright 2017 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 BROWSER_DEVTOOLS_PROTOCOL_PAGE_HANDLER_IMAGE_UTILS_H_
+#define BROWSER_DEVTOOLS_PROTOCOL_PAGE_HANDLER_IMAGE_UTILS_H_
+
+#include "base/macros.h"
+
+namespace content {
+namespace protocol {
+
+enum class ScreenshotFormat { PNG, JPEG };
+
+// base64-encodes the provided gfx::Image as PNG or JPEG.
+std::string EncodeScreenshotImage(const gfx::Image& image,
+                                  ScreenshotFormat format,
+                                  int quality);
+
+scoped_refptr<base::RefCountedMemory> EncodeScreenshotImageAsJpeg(
+    const gfx::Image& image,
+    int quality);
+
+}  // namespace protocol
+}  // namespace content
+
+#endif  // BROWSER_DEVTOOLS_PROTOCOL_PAGE_HANDLER_IMAGE_UTILS_H_