Mark all virtual overrides in the hierarchy of AudioPacketizationCallback,
RTPStream, and NetEq as such.  Also mark all other virtual overrides in the same
files.

This will make further changes to these classes safer by ensuring that the
compile breaks if the base class changes and not all overrides are fixed.

This also deletes ACMTest.cc, which existed solely to define ~ACMTest(), which
was marked pure virtual in the header.  (Pure virtual destructors still need a
definition.)  Because there is another pure virtual method in this class, the
class is already abstract, so there's no benefit to making the desturctor pure.
Making it non-pure allows removing the separate source file.

BUG=none
TEST=none
R=henrik.lundin@webrtc.org, niklas.enbom@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/29389004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7144 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/main/test/TestAllCodecs.h b/webrtc/modules/audio_coding/main/test/TestAllCodecs.h
index 73eac47..2fbf9ef 100644
--- a/webrtc/modules/audio_coding/main/test/TestAllCodecs.h
+++ b/webrtc/modules/audio_coding/main/test/TestAllCodecs.h
@@ -28,10 +28,11 @@
 
   void RegisterReceiverACM(AudioCodingModule* acm);
 
-  int32_t SendData(FrameType frame_type, uint8_t payload_type,
-                   uint32_t timestamp, const uint8_t* payload_data,
-                   uint16_t payload_size,
-                   const RTPFragmentationHeader* fragmentation);
+  virtual int32_t SendData(
+      FrameType frame_type, uint8_t payload_type,
+      uint32_t timestamp, const uint8_t* payload_data,
+      uint16_t payload_size,
+      const RTPFragmentationHeader* fragmentation) OVERRIDE;
 
   uint16_t payload_size();
   uint32_t timestamp_diff();
@@ -52,7 +53,7 @@
   explicit TestAllCodecs(int test_mode);
   ~TestAllCodecs();
 
-  void Perform();
+  virtual void Perform() OVERRIDE;
 
  private:
   // The default value of '-1' indicates that the registration is based only on