Update {virtual,override} to follow C++11 style in content.

content/renderer/media/video_capture_message_filter_unittest.cc

Index: content/renderer/media/video_capture_message_filter_unittest.cc
diff --git a/content/renderer/media/video_capture_message_filter_unittest.cc b/content/renderer/media/video_capture_message_filter_unittest.cc
index 72fd23554a77039e0dde1085466bf5776b27f929..e2660b9259c517255b1d5fa40f3a991cb9fb963b 100644
--- a/content/renderer/media/video_capture_message_filter_unittest.cc
+++ b/content/renderer/media/video_capture_message_filter_unittest.cc
@@ -50,7 +50,7 @@ class MockVideoCaptureDelegate : public VideoCaptureMessageFilter::Delegate {
   MOCK_METHOD1(OnDeviceFormatsInUseReceived,
                void(const media::VideoCaptureFormats& formats_in_use));
 
-  virtual void OnDelegateAdded(int32 device_id) override {
+  void OnDelegateAdded(int32 device_id) override {
     ASSERT_TRUE(device_id != 0);
     ASSERT_TRUE(device_id_ == 0);
     device_id_ = device_id;