Make GetBitstream non-virtual since it is no longer needed for testing.

Bug: webrtc:10979
Change-Id: Id313c7fddbec40b9f19dae95f736379b872e3082
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/153663
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29242}

modules/video_coding/packet_buffer.h

@@ -114,8 +114,7 @@ class PacketBuffer {
       RTC_EXCLUSIVE_LOCKS_REQUIRED(crit_);
 
   // Copy the bitstream for |frame| to |destination|.
-  // Virtual for testing.
-  virtual bool GetBitstream(const RtpFrameObject& frame, uint8_t* destination);
+  bool GetBitstream(const RtpFrameObject& frame, uint8_t* destination);
 
   // Get the packet with sequence number |seq_num|.
   // Virtual for testing.

modules/video_coding/rtp_frame_reference_finder_unittest.cc

@@ -40,11 +40,6 @@ class FakePacketBuffer : public PacketBuffer {
     return true;
   }
 
-  bool GetBitstream(const RtpFrameObject& frame,
-                    uint8_t* destination) override {
-    return true;
-  }
-
  private:
   std::map<uint16_t, VCMPacket> packets_;
 };

test/fuzzers/rtp_frame_reference_finder_fuzzer.cc

@@ -100,11 +100,6 @@ class FuzzyPacketBuffer : public video_coding::PacketBuffer {
     return packet;
   }
 
-  bool GetBitstream(const video_coding::RtpFrameObject& frame,
-                    uint8_t* destination) override {
-    return true;
-  }
-
  private:
   std::map<uint16_t, VCMPacket> packets;
   VideoCodecType codec;

video/buffered_frame_decryptor_unittest.cc

@@ -41,11 +41,6 @@ class FakePacketBuffer : public video_coding::PacketBuffer {
     return true;
   }
 
-  bool GetBitstream(const video_coding::RtpFrameObject& frame,
-                    uint8_t* destination) override {
-    return true;
-  }
-
  private:
   std::map<uint16_t, VCMPacket> packets_;
 };