Fix coding style nits.

uint32_t parameters don't need to be passed by reference. The
VCMJitterBuffer destructor doesn't need to be virtual because the
class has no virtual methods.

R=stefan@webrtc.org
BUG=none

Review URL: https://webrtc-codereview.appspot.com/55499004

Cr-Commit-Position: refs/heads/master@{#9288}
diff --git a/webrtc/modules/video_coding/main/source/jitter_buffer.h b/webrtc/modules/video_coding/main/source/jitter_buffer.h
index 5ccc92e..1be2606 100644
--- a/webrtc/modules/video_coding/main/source/jitter_buffer.h
+++ b/webrtc/modules/video_coding/main/source/jitter_buffer.h
@@ -54,8 +54,8 @@
 
 class TimestampLessThan {
  public:
-  bool operator() (const uint32_t& timestamp1,
-                   const uint32_t& timestamp2) const {
+  bool operator() (uint32_t timestamp1,
+                   uint32_t timestamp2) const {
     return IsNewerTimestamp(timestamp2, timestamp1);
   }
 };
@@ -78,7 +78,7 @@
  public:
   VCMJitterBuffer(Clock* clock,
                   EventFactory* event_factory);
-  virtual ~VCMJitterBuffer();
+  ~VCMJitterBuffer();
 
   // Initializes and starts jitter buffer.
   void Start();