Fix crash when view is already deleted

content/browser/media/capture/web_contents_video_capture_device.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.
 //
 // Implementation notes: This needs to work on a variety of hardware
 // configurations where the speed of the CPU and GPU greatly affect overall
 // performance. Spanning several threads, the process of capturing has been
 // split up into four conceptual stages:
 //
 //   1. Reserve Buffer: Before a frame can be captured, a slot in the client's
@@ skipping 425 matching lines @@
 // https://crbug.com/554280 https://crbug.com/549182
 #if defined(USE_AURA) && defined(OS_LINUX)
   if (view) {
     cursor_renderer_.reset(
         new content::CursorRendererAura(view->GetNativeView()));
   }
 #endif
 // TODO(isheriff): Needs implementation on non-aura platforms.
 // https://crbug.com/567735
 #if defined(USE_AURA)
-  window_activity_tracker_.reset(
-      new content::WindowActivityTrackerAura(view->GetNativeView()));
+  if (view) {

[miu, 2015/12/30 00:22:40]

Possible clean-up in future CL: Looks like we should just check the view at the
top of this method and return early if nullptr.  Or, maybe the caller should not
instantiate a ContentCaptureSubscription if the view is null?

[Irfan, 2015/12/30 00:32:12]

I like not instantiating ContentCaptureSubscription when view is null, but I
leave this as-is right now.

+    window_activity_tracker_.reset(
+        new content::WindowActivityTrackerAura(view->GetNativeView()));
+  }
 #endif
   timer_subscriber_.reset(new FrameSubscriber(
       media::VideoCaptureOracle::kTimerPoll, oracle_proxy, &delivery_log_,
       cursor_renderer_ ? cursor_renderer_->GetWeakPtr()
                        : base::WeakPtr<CursorRenderer>(),
       window_activity_tracker_ ? window_activity_tracker_->GetWeakPtr()
                                : base::WeakPtr<WindowActivityTracker>()));
 
   // Subscribe to compositor updates. These will be serviced directly by the
   // oracle.
@@ skipping 508 matching lines @@
     scoped_ptr<Client> client) {
   DVLOG(1) << "Allocating " << params.requested_format.frame_size.ToString();
   core_->AllocateAndStart(params, client.Pass());
 }
 
 void WebContentsVideoCaptureDevice::StopAndDeAllocate() {
   core_->StopAndDeAllocate();
 }
 
 }  // namespace content