Delete Timing class, timing.h, and update all users.

BUG=webrtc:6324

Review-Url: https://codereview.webrtc.org/2290203002
Cr-Commit-Position: refs/heads/master@{#14203}
diff --git a/webrtc/media/base/rtpdataengine.h b/webrtc/media/base/rtpdataengine.h
index 0181e65..98f90be 100644
--- a/webrtc/media/base/rtpdataengine.h
+++ b/webrtc/media/base/rtpdataengine.h
@@ -15,7 +15,6 @@
 #include <string>
 #include <vector>
 
-#include "webrtc/base/timing.h"
 #include "webrtc/media/base/mediachannel.h"
 #include "webrtc/media/base/mediaconstants.h"
 #include "webrtc/media/base/mediaengine.h"
@@ -34,14 +33,8 @@
     return data_codecs_;
   }
 
-  // Mostly for testing with a fake clock.  Ownership is passed in.
-  void SetTiming(rtc::Timing* timing) {
-    timing_.reset(timing);
-  }
-
  private:
   std::vector<DataCodec> data_codecs_;
-  std::unique_ptr<rtc::Timing> timing_;
 };
 
 // Keep track of sequence number and timestamp of an RTP stream.  The
@@ -68,17 +61,9 @@
 
 class RtpDataMediaChannel : public DataMediaChannel {
  public:
-  // Timing* Used for the RtpClock
-  explicit RtpDataMediaChannel(rtc::Timing* timing);
-  // Sets Timing == NULL, so you'll need to call set_timer() before
-  // using it.  This is needed by FakeMediaEngine.
   RtpDataMediaChannel();
   virtual ~RtpDataMediaChannel();
 
-  void set_timing(rtc::Timing* timing) {
-    timing_ = timing;
-  }
-
   virtual bool SetSendParameters(const DataSendParameters& params);
   virtual bool SetRecvParameters(const DataRecvParameters& params);
   virtual bool AddSendStream(const StreamParams& sp);
@@ -104,14 +89,13 @@
     SendDataResult* result);
 
  private:
-  void Construct(rtc::Timing* timing);
+  void Construct();
   bool SetMaxSendBandwidth(int bps);
   bool SetSendCodecs(const std::vector<DataCodec>& codecs);
   bool SetRecvCodecs(const std::vector<DataCodec>& codecs);
 
   bool sending_;
   bool receiving_;
-  rtc::Timing* timing_;
   std::vector<DataCodec> send_codecs_;
   std::vector<DataCodec> recv_codecs_;
   std::vector<StreamParams> send_streams_;