android: Remove in-process sync compositor code path

content/renderer/android/synchronous_compositor_factory.cc

-// Copyright 2013 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 "content/renderer/android/synchronous_compositor_factory.h"
-
-#include "base/logging.h"
-
-namespace content {
-
-namespace {
-SynchronousCompositorFactory* g_instance = nullptr;
-}  // namespace
-
-// static
-void SynchronousCompositorFactory::SetInstance(
-    SynchronousCompositorFactory* instance) {
-  DCHECK(g_instance == nullptr);
-  g_instance = instance;
-}
-
-// static
-SynchronousCompositorFactory* SynchronousCompositorFactory::GetInstance() {
-  return g_instance;
-}
-
-}  // namespace content