Revert of Delete class SSRCDatabase, and its global ssrc registry.

webrtc/voice_engine/channel_manager.cc

Index: webrtc/voice_engine/channel_manager.cc
diff --git a/webrtc/voice_engine/channel_manager.cc b/webrtc/voice_engine/channel_manager.cc
index b81c8a63cc98a185ea5f40667e35f786590b28b3..b8ffe6e796c239734e4748fd1e5d87305bdc527f 100644
--- a/webrtc/voice_engine/channel_manager.cc
+++ b/webrtc/voice_engine/channel_manager.cc
@@ -10,7 +10,6 @@
 
 #include "webrtc/voice_engine/channel_manager.h"
 
-#include "webrtc/base/timeutils.h"
 #include "webrtc/voice_engine/channel.h"
 
 namespace webrtc {
@@ -46,18 +45,12 @@
     : channel(channel), ref_count(1) {}
 
 ChannelManager::ChannelManager(uint32_t instance_id)
-    : instance_id_(instance_id),
-      last_channel_id_(-1),
-      random_(rtc::TimeNanos()) {}
+    : instance_id_(instance_id), last_channel_id_(-1) {}
 
 ChannelOwner ChannelManager::CreateChannel(
     const VoEBase::ChannelConfig& config) {
   Channel* channel;
   Channel::CreateChannel(channel, ++last_channel_id_, instance_id_, config);
-  // TODO(solenberg): Delete this, users should configure ssrc
-  // explicitly.
-  channel->SetLocalSSRC(random_.Rand<uint32_t>());
-
   ChannelOwner channel_owner(channel);
 
   rtc::CritScope crit(&lock_);