Attempt to fixed crash on stop mirroring by stopping render thread on a worker thread.

content/browser/renderer_host/media/desktop_capture_device_aura.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/browser/renderer_host/media/desktop_capture_device_aura.h"
 
 #include "base/logging.h"
 #include "base/timer/timer.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/output/copy_output_result.h"
@@ skipping 79 matching lines @@
       public aura::WindowObserver,
       public ui::CompositorObserver,
       public base::SupportsWeakPtr<DesktopVideoCaptureMachine> {
  public:
   DesktopVideoCaptureMachine(const DesktopMediaID& source);
   virtual ~DesktopVideoCaptureMachine();
 
   // VideoCaptureFrameSource overrides.
   virtual bool Start(
       const scoped_refptr<ThreadSafeCaptureOracle>& oracle_proxy) OVERRIDE;
-  virtual void Stop() OVERRIDE;
+  virtual void Stop(const base::Closure& callback) OVERRIDE;
 
   // Implements aura::WindowObserver.
   virtual void OnWindowBoundsChanged(aura::Window* window,
                                      const gfx::Rect& old_bounds,
                                      const gfx::Rect& new_bounds) OVERRIDE;
   virtual void OnWindowDestroyed(aura::Window* window) OVERRIDE;
 
   // Implements ui::CompositorObserver.
   virtual void OnCompositingDidCommit(ui::Compositor* compositor) OVERRIDE {}
   virtual void OnCompositingStarted(ui::Compositor* compositor,
@@ skipping 95 matching lines @@
 
   // Starts timer.
   timer_.Start(FROM_HERE, oracle_proxy_->capture_period(),
                base::Bind(&DesktopVideoCaptureMachine::Capture, AsWeakPtr(),
                           false));
 
   started_ = true;
   return true;
 }
 
-void DesktopVideoCaptureMachine::Stop() {
+void DesktopVideoCaptureMachine::Stop(const base::Closure& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   // Stop observing window events.
   if (desktop_window_) {
     desktop_window_->RemoveObserver(this);
     desktop_window_ = NULL;
   }
 
   // Stop observing compositor updates.
   if (desktop_layer_) {
     ui::Compositor* compositor = desktop_layer_->GetCompositor();
     if (compositor)
       compositor->RemoveObserver(this);
     desktop_layer_ = NULL;
   }
 
   // Stop timer.
   timer_.Stop();
 
   started_ = false;
+
+  callback.Run();
 }
 
 void DesktopVideoCaptureMachine::UpdateCaptureSize() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   if (oracle_proxy_ && desktop_layer_) {
     oracle_proxy_->UpdateCaptureSize(ui::ConvertSizeToPixel(
         desktop_layer_, desktop_layer_->bounds().size()));
   }
   ClearCursorState();
 }
@@ skipping 147 matching lines @@
   DCHECK(desktop_window_ && window == desktop_window_);
 
   // Post task to update capture size on UI thread.
   BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, base::Bind(
       &DesktopVideoCaptureMachine::UpdateCaptureSize, AsWeakPtr()));
 }
 
 void DesktopVideoCaptureMachine::OnWindowDestroyed(aura::Window* window) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  Stop();
+  Stop(base::Bind(&base::DoNothing));
 
   oracle_proxy_->ReportError();
 }
 
 void DesktopVideoCaptureMachine::OnCompositingEnded(
     ui::Compositor* compositor) {
   BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, base::Bind(
       &DesktopVideoCaptureMachine::Capture, AsWeakPtr(), true));
 }
 
@@ skipping 19 matching lines @@
     scoped_ptr<Client> client) {
   DVLOG(1) << "Allocating " << params.requested_format.frame_size.ToString();
   impl_->AllocateAndStart(params, client.Pass());
 }
 
 void DesktopCaptureDeviceAura::StopAndDeAllocate() {
   impl_->StopAndDeAllocate();
 }
 
 }  // namespace content