Simplify ScreenCapturer interface.

media/video/capture/screen/screen_capture_device.cc

 // Copyright (c) 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 "media/video/capture/screen/screen_capture_device.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/sequenced_task_runner.h"
@@ skipping 290 matching lines @@
 
 void ScreenCaptureDevice::Core::DoStop() {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
   started_ = false;
   resized_bitmap_.reset();
 }
 
 void ScreenCaptureDevice::Core::DoDeAllocate() {
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
   DoStop();
-  if (screen_capturer_) {
-    screen_capturer_->Stop();
-    screen_capturer_.reset();
-  }
+  screen_capturer_.reset();
   waiting_for_frame_size_ = false;
 }
 
 void ScreenCaptureDevice::Core::ScheduleCaptureTimer() {
   DCHECK(!capture_task_posted_);
   capture_task_posted_ = true;
   task_runner_->PostDelayedTask(
       FROM_HERE, base::Bind(&Core::OnCaptureTimer, this),
       base::TimeDelta::FromSeconds(1) / frame_rate_);
 }
@@ skipping 55 matching lines @@
 
 void ScreenCaptureDevice::DeAllocate() {
   core_->DeAllocate();
 }
 
 const VideoCaptureDevice::Name& ScreenCaptureDevice::device_name() {
   return name_;
 }
 
 }  // namespace media