Fix obsolete comment

We support GpuMemoryBuffer-based buffer in FakeVideoCaptureDevice now [1],
so update the comment accordingly.

[1]: https://crrev.com/c/1863055

Bug: 982201
Change-Id: I8108e3f45caf4d9eead3d3c88ea1a8e5f31adc1d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1890381Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Commit-Queue: Ricky Liang <jcliang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711577}

content/browser/renderer_host/media/service_video_capture_device_launcher.cc

@@ -140,8 +140,7 @@ void ServiceVideoCaptureDeviceLauncher::LaunchDeviceAsync(
       media::VideoCaptureDevice::GetPowerLineFrequency(params);
 
   // GpuMemoryBuffer-based VideoCapture buffer works only on the Chrome OS
-  // VideoCaptureDevice implementation. It's not supported by
-  // FakeVideoCaptureDevice.
+  // VideoCaptureDevice implementation.
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kVideoCaptureUseGpuMemoryBuffer)) {
     new_params.buffer_type = media::VideoCaptureBufferType::kGpuMemoryBuffer;