Fix for ~ContentCaptureSubscription() after BrowserThreads are torn down.

content/browser/media/capture/web_contents_video_capture_device.cc

Index: content/browser/media/capture/web_contents_video_capture_device.cc
diff --git a/content/browser/media/capture/web_contents_video_capture_device.cc b/content/browser/media/capture/web_contents_video_capture_device.cc
index 2ddeb2b9eedbd5e960dbf5108edfb2ae7ed53481..654b8dcc0ff4ed89486fe74539b8e88971e8183c 100644
--- a/content/browser/media/capture/web_contents_video_capture_device.cc
+++ b/content/browser/media/capture/web_contents_video_capture_device.cc
@@ -371,7 +371,7 @@ ContentCaptureSubscription::ContentCaptureSubscription(
                         &delivery_log_),
       capture_callback_(capture_callback),
       timer_(true, true) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   RenderWidgetHostViewBase* view = static_cast<RenderWidgetHostViewBase*>(
       source.GetView());
@@ -399,7 +399,13 @@ ContentCaptureSubscription::ContentCaptureSubscription(
 }
 
 ContentCaptureSubscription::~ContentCaptureSubscription() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  // If the BrowserThreads have been torn down, then the browser is in the final
+  // stages of exiting and it is dangerous to take any further action.  We must
+  // return early.  http://crbug.com/396413
+  if (!BrowserThread::IsMessageLoopValid(BrowserThread::UI))

[miu, 2014/08/28 01:59:56]

This is the fix: Calling RenderViewHost::FromID(...) is invalid after the UI
BrowserThreadImpl has been torn down.

+    return;
+
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (kAcceleratedSubscriberIsSupported) {
     RenderViewHost* source = RenderViewHost::FromID(render_process_id_,
                                                     render_view_id_);
@@ -416,7 +422,7 @@ void ContentCaptureSubscription::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK_EQ(NOTIFICATION_RENDER_WIDGET_HOST_DID_UPDATE_BACKING_STORE, type);
 
   RenderWidgetHostImpl* rwh =
@@ -455,7 +461,7 @@ void ContentCaptureSubscription::Observe(
 }
 
 void ContentCaptureSubscription::OnTimer() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   TRACE_EVENT0("mirroring", "ContentCaptureSubscription::OnTimer");
 
   scoped_refptr<media::VideoFrame> frame;
@@ -575,18 +581,13 @@ WebContentsCaptureMachine::WebContentsCaptureMachine(int render_process_id,
       fullscreen_widget_id_(MSG_ROUTING_NONE),
       weak_ptr_factory_(this) {}
 
-WebContentsCaptureMachine::~WebContentsCaptureMachine() {
-  BrowserThread::PostBlockingPoolTask(
-      FROM_HERE,
-      base::Bind(&DeleteOnWorkerThread, base::Passed(&render_thread_),
-                 base::Bind(&base::DoNothing)));
-}
+WebContentsCaptureMachine::~WebContentsCaptureMachine() {}
 
 bool WebContentsCaptureMachine::Start(
     const scoped_refptr<ThreadSafeCaptureOracle>& oracle_proxy,
     const media::VideoCaptureParams& params) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DCHECK(!started_);
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DCHECK(!weak_ptr_factory_.HasWeakPtrs());  // Should not be started.
 
   DCHECK(oracle_proxy.get());
   oracle_proxy_ = oracle_proxy;
@@ -605,12 +606,11 @@ bool WebContentsCaptureMachine::Start(
     return false;
   }
 
-  started_ = true;
   return true;
 }
 
 void WebContentsCaptureMachine::Stop(const base::Closure& callback) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   subscription_.reset();
   if (web_contents()) {
     web_contents()->DecrementCapturerCount();
@@ -623,12 +623,12 @@ void WebContentsCaptureMachine::Stop(const base::Closure& callback) {
 
   // The render thread cannot be stopped on the UI thread, so post a message
   // to the thread pool used for blocking operations.
-  BrowserThread::PostBlockingPoolTask(
-      FROM_HERE,
-      base::Bind(&DeleteOnWorkerThread, base::Passed(&render_thread_),
-                 callback));
-
-  started_ = false;
+  if (render_thread_.get()) {
+    BrowserThread::PostBlockingPoolTask(
+        FROM_HERE,
+        base::Bind(&DeleteOnWorkerThread, base::Passed(&render_thread_),
+                   callback));
+  }
 }
 
 void WebContentsCaptureMachine::Capture(
@@ -636,7 +636,7 @@ void WebContentsCaptureMachine::Capture(
     const scoped_refptr<media::VideoFrame>& target,
     const RenderWidgetHostViewFrameSubscriber::DeliverFrameCallback&
         deliver_frame_cb) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   RenderWidgetHost* rwh = GetTarget();
   RenderWidgetHostViewBase* view =
@@ -683,7 +683,7 @@ void WebContentsCaptureMachine::Capture(
 }
 
 gfx::Size WebContentsCaptureMachine::ComputeOptimalTargetSize() const {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   gfx::Size optimal_size = oracle_proxy_->GetCaptureSize();
 
@@ -714,7 +714,7 @@ gfx::Size WebContentsCaptureMachine::ComputeOptimalTargetSize() const {
 }
 
 bool WebContentsCaptureMachine::StartObservingWebContents() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   // Look-up the RenderFrameHost and, from that, the WebContents that wraps it.
   // If successful, begin observing the WebContents instance.
@@ -743,7 +743,7 @@ bool WebContentsCaptureMachine::StartObservingWebContents() {
 }
 
 void WebContentsCaptureMachine::WebContentsDestroyed() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   subscription_.reset();
   web_contents()->DecrementCapturerCount();
@@ -751,7 +751,7 @@ void WebContentsCaptureMachine::WebContentsDestroyed() {
 }
 
 RenderWidgetHost* WebContentsCaptureMachine::GetTarget() const {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (!web_contents())
     return NULL;
 
@@ -774,7 +774,7 @@ void WebContentsCaptureMachine::DidCopyFromBackingStore(
         deliver_frame_cb,
     bool success,
     const SkBitmap& bitmap) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   base::TimeTicks now = base::TimeTicks::Now();
   DCHECK(render_thread_.get());
@@ -797,7 +797,7 @@ void WebContentsCaptureMachine::DidCopyFromCompositingSurfaceToVideoFrame(
     const RenderWidgetHostViewFrameSubscriber::DeliverFrameCallback&
         deliver_frame_cb,
     bool success) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   base::TimeTicks now = base::TimeTicks::Now();
 
   if (success) {
@@ -810,7 +810,7 @@ void WebContentsCaptureMachine::DidCopyFromCompositingSurfaceToVideoFrame(
 }
 
 void WebContentsCaptureMachine::RenewFrameSubscription() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   // Always destroy the old subscription before creating a new one.
   subscription_.reset();
@@ -839,7 +839,7 @@ WebContentsVideoCaptureDevice::~WebContentsVideoCaptureDevice() {
 // static
 media::VideoCaptureDevice* WebContentsVideoCaptureDevice::Create(
     const std::string& device_id) {
-  // Parse device_id into render_process_id and render_view_id.
+  // Parse device_id into render_process_id and main_render_frame_id.
   int render_process_id = -1;
   int main_render_frame_id = -1;
   if (!WebContentsCaptureUtil::ExtractTabCaptureTarget(