Revert of Always use an external begin frame source in the renderer

content/renderer/render_thread_impl.cc

 // Copyright (c) 2012 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/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <utility>
@@ skipping 1604 matching lines @@
 gpu::GpuMemoryBufferManager* RenderThreadImpl::GetGpuMemoryBufferManager() {
   return gpu_memory_buffer_manager();
 }
 
 blink::scheduler::RendererScheduler* RenderThreadImpl::GetRendererScheduler() {
   return renderer_scheduler_.get();
 }
 
 std::unique_ptr<cc::BeginFrameSource>
 RenderThreadImpl::CreateExternalBeginFrameSource(int routing_id) {
-  const base::CommandLine* command_line =
-      base::CommandLine::ForCurrentProcess();
-
-  if (command_line->HasSwitch(switches::kUseRemoteCompositing) ||
-      command_line->HasSwitch(switches::kIsRunningInMash) ||
-      command_line->HasSwitch(cc::switches::kDisableBeginFrameScheduling)) {
-    return base::WrapUnique(new cc::DelayBasedBeginFrameSource(
-        base::MakeUnique<cc::DelayBasedTimeSource>(
-            compositor_task_runner_
-                ? compositor_task_runner_.get()
-                : main_thread_compositor_task_runner_.get())));
-  }
-
   return base::WrapUnique(new CompositorExternalBeginFrameSource(
       compositor_message_filter_.get(), sync_message_filter(), routing_id));
 }
 
 cc::ImageSerializationProcessor*
 RenderThreadImpl::GetImageSerializationProcessor() {
   return GetContentClient()->renderer()->GetImageSerializationProcessor();
 }
 
 cc::TaskGraphRunner* RenderThreadImpl::GetTaskGraphRunner() {
@@ skipping 606 matching lines @@
       v8_memory_pressure_level == v8::MemoryPressureLevel::kCritical)
     v8_memory_pressure_level = v8::MemoryPressureLevel::kModerate;
 
   blink::mainThreadIsolate()->MemoryPressureNotification(
       v8_memory_pressure_level);
   blink::MemoryPressureNotificationToWorkerThreadIsolates(
       v8_memory_pressure_level);
 }
 
 }  // namespace content