Revert of Enable -Winconsistent-missing-override flag.

webrtc/video/vie_channel.h

Index: webrtc/video/vie_channel.h
diff --git a/webrtc/video/vie_channel.h b/webrtc/video/vie_channel.h
index 92adc4ed93d93a72953f8932be5c78601fae1930..041185782696582bf7c2427050e369351299de5a 100644
--- a/webrtc/video/vie_channel.h
+++ b/webrtc/video/vie_channel.h
@@ -81,10 +81,11 @@
   CallStatsObserver* GetStatsObserver();
 
   // Implements VCMReceiveCallback.
-  int32_t FrameToRender(VideoFrame& video_frame) override;  // NOLINT
+  virtual int32_t FrameToRender(VideoFrame& video_frame);  // NOLINT
 
   // Implements VCMReceiveCallback.
-  int32_t ReceivedDecodedReferenceFrame(const uint64_t picture_id) override;
+  virtual int32_t ReceivedDecodedReferenceFrame(
+      const uint64_t picture_id);
 
   // Implements VCMReceiveCallback.
   void OnIncomingPayloadType(int payload_type) override;
@@ -96,20 +97,20 @@
   void OnFrameCountsUpdated(const FrameCounts& frame_counts) override;
 
   // Implements VCMDecoderTimingCallback.
-  void OnDecoderTiming(int decode_ms,
-                       int max_decode_ms,
-                       int current_delay_ms,
-                       int target_delay_ms,
-                       int jitter_buffer_ms,
-                       int min_playout_delay_ms,
-                       int render_delay_ms) override;
+  virtual void OnDecoderTiming(int decode_ms,
+                               int max_decode_ms,
+                               int current_delay_ms,
+                               int target_delay_ms,
+                               int jitter_buffer_ms,
+                               int min_playout_delay_ms,
+                               int render_delay_ms);
 
   // Implements FrameTypeCallback.
-  int32_t RequestKeyFrame() override;
+  virtual int32_t RequestKeyFrame();
 
   // Implements FrameTypeCallback.
-  int32_t SliceLossIndicationRequest(
-      const uint64_t picture_id) override;
+  virtual int32_t SliceLossIndicationRequest(
+      const uint64_t picture_id);
 
   // Implements VideoPacketRequestCallback.
   int32_t ResendPackets(const uint16_t* sequence_numbers,