VCD: Fix the race condition when closing CameraAppDeviceImpl

After https://crrev.com/c/2602969, |OnDeviceClosed()| might be triggered
from different threads. But in |OnDeviceClosed()|, it will access
|camera_app_devices_| and might introduce race condition.

Therefore, to fix it, we can post the task to make sure that
|OnDeviceClosed()| will be called on the same thread.

And since now we will not call |OnDeviceClosed()| directly and the mojo
error handler of a receiver set might be triggered more than once, we
should also handle it properly.

Bug: b/177191321
Test: Consecutively passes CCAUISettings.swa for 20 times

Change-Id: I93e546a98c410017f17071c97336bfe40dcc7b69
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2619247
Commit-Queue: Wei Lee <wtlee@chromium.org>
Commit-Queue: Shik Chen <shik@chromium.org>
Auto-Submit: Wei Lee <wtlee@chromium.org>
Reviewed-by: Shik Chen <shik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841974}

media/capture/video/chromeos/camera_app_device_bridge_impl.cc

@@ -7,6 +7,7 @@
 #include <string>
 
 #include "base/command_line.h"
+#include "media/base/bind_to_current_loop.h"
 #include "media/base/media_switches.h"
 #include "media/capture/video/chromeos/public/cros_features.h"
 #include "media/capture/video/chromeos/video_capture_device_chromeos_halv3.h"
@@ -69,8 +70,9 @@ media::CameraAppDeviceImpl* CameraAppDeviceBridgeImpl::CreateCameraAppDevice(
   auto device_info = camera_info_getter_.Run(device_id);
   auto device_impl = std::make_unique<media::CameraAppDeviceImpl>(
       device_id, std::move(device_info),
-      base::BindOnce(&CameraAppDeviceBridgeImpl::OnDeviceClosed,
-                     base::Unretained(this), device_id));
+      media::BindToCurrentLoop(
+          base::BindOnce(&CameraAppDeviceBridgeImpl::OnDeviceClosed,
+                         base::Unretained(this), device_id)));
   auto result = camera_app_devices_.emplace(device_id, std::move(device_impl));
   return result.first->second.get();
 }

media/capture/video/chromeos/camera_app_device_impl.cc

@@ -295,7 +295,11 @@ void CameraAppDeviceImpl::DisableEeNr(ReprocessTask* task) {
 }
 
 void CameraAppDeviceImpl::OnMojoConnectionError() {
-  std::move(cleanup_callback_).Run();
+  // Since it is the error handler of a receiver set, it might be triggered more
+  // than once.
+  if (!cleanup_callback_.is_null()) {
+    std::move(cleanup_callback_).Run();
+  }
 }
 
 void CameraAppDeviceImpl::SetReprocessResultOnMojoThread(