Fix a null ptr deref crash in DesktopCaptureDevice

content/browser/media/capture/desktop_capture_device.cc

Index: content/browser/media/capture/desktop_capture_device.cc
diff --git a/content/browser/media/capture/desktop_capture_device.cc b/content/browser/media/capture/desktop_capture_device.cc
index 0ddcf2698cae148732a85b5eaa26fb190d661869..fe294216ca729a8efb4794ba3018585b676af097 100644
--- a/content/browser/media/capture/desktop_capture_device.cc
+++ b/content/browser/media/capture/desktop_capture_device.cc
@@ -466,10 +466,14 @@ void DesktopCaptureDevice::StopAndDeAllocate() {
 
 void DesktopCaptureDevice::SetNotificationWindowId(
     gfx::NativeViewId window_id) {
-  thread_.message_loop_proxy()->PostTask(
-      FROM_HERE,
-      base::Bind(&Core::SetNotificationWindowId, base::Unretained(core_.get()),
-                 window_id));
+  // This may be called after the capturer has been stopped.
+  if (thread_.message_loop_proxy()) {

[Sergey Ulanov, 2015/02/03 17:49:18]

I'd prefer checking that core_ is not nullptr here instead of
message_loop_proxy()

Also message_loop_proxy() is deprecated. task_runner() should be used instead.

[jiayl, 2015/02/03 17:54:09]

Done.

+    thread_.message_loop_proxy()->PostTask(
+        FROM_HERE,
+        base::Bind(&Core::SetNotificationWindowId,
+                   base::Unretained(core_.get()),
+                   window_id));
+  }
 }
 
 DesktopCaptureDevice::DesktopCaptureDevice(