Revert of [devtools] Support different encodings for Page.CaptureScreenshot.

ui/snapshot/snapshot.cc

-// 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.
-
-#include "ui/snapshot/snapshot.h"
-
-#include "base/bind.h"
-#include "base/callback.h"
-#include "base/task_runner_util.h"
-#include "ui/gfx/image/image.h"
-
-namespace ui {
-
-namespace {
-
-scoped_refptr<base::RefCountedMemory> EncodeImage(const gfx::Image& image) {
-  return image.As1xPNGBytes();
-}
-
-void EncodeImageAndSchedulePNGCallback(
-    scoped_refptr<base::TaskRunner> background_task_runner,
-    const GrabWindowSnapshotAsyncPNGCallback& callback,
-    const gfx::Image& image) {
-  base::PostTaskAndReplyWithResult(background_task_runner.get(), FROM_HERE,
-                                   base::Bind(EncodeImage, image), callback);
-}
-
-}  // namespace
-
-void GrabWindowSnapshotAsyncPNG(
-    gfx::NativeWindow window,
-    const gfx::Rect& source_rect,
-    scoped_refptr<base::TaskRunner> background_task_runner,
-    const GrabWindowSnapshotAsyncPNGCallback& callback) {
-  GrabWindowSnapshotAsync(
-      window, source_rect,
-      base::Bind(EncodeImageAndSchedulePNGCallback,
-                 std::move(background_task_runner), callback));
-}
-
-}  // namespace ui