Add UMA metrics for ICE regathering reasons.

webrtc/p2p/base/portallocator.h

Index: webrtc/p2p/base/portallocator.h
diff --git a/webrtc/p2p/base/portallocator.h b/webrtc/p2p/base/portallocator.h
index 8befbadcc73981375d22ba23b321c417fbb2cd21..747b0dd3ab528bcb28d3babf3f00b3bfeab6b733 100644
--- a/webrtc/p2p/base/portallocator.h
+++ b/webrtc/p2p/base/portallocator.h
@@ -23,6 +23,10 @@
 #include "webrtc/base/sigslot.h"
 #include "webrtc/base/thread.h"
 
+namespace webrtc {
+class MetricsObserverInterface;
+}
+
 namespace cricket {
 
 // PortAllocator is responsible for allocating Port types for a given
@@ -72,6 +76,16 @@ enum {
   PORTALLOCATOR_DISABLE_COSTLY_NETWORKS = 0x2000,
 };
 
+// Defines various reasons that have caused ICE regathering.
+enum class IceRegatheringReason {
+  ICE_RESTART_WHEN_CONNECTED,
+  ICE_RESTART_WHEN_CONNECTING,
+  ICE_RESTART_WHEN_DISCONNECTED,

[pthatcher2, 2016/10/04 06:03:17]

Shouldn't these be "_WHILE_" rather than "_WHEN_"?

[honghaiz3, 2016/10/05 05:01:53]

renamed class and variables as suggested in other comments.

+  CONTINUAL_GATHERING_BY_NETWORK_CHANGE,
+  CONTINUAL_GATHERING_BY_NETWORK_FAILURE,

[pthatcher2, 2016/10/04 06:03:17]

Shouldn't these be "_FOR_" rather than "_BY_"?

[honghaiz3, 2016/10/05 05:01:53]

Renames this too. 

+  MAX_VALUE
+};
+
 const uint32_t kDefaultPortAllocatorFlags = 0;
 
 const uint32_t kDefaultStepDelay = 1000;  // 1 sec step delay.
@@ -216,6 +230,8 @@ class PortAllocatorSession : public sigslot::has_slots<> {
       SignalCandidatesRemoved;
   sigslot::signal1<PortAllocatorSession*> SignalCandidatesAllocationDone;
 
+  sigslot::signal1<IceRegatheringReason> SignalIceRegatheringReason;

[pthatcher2, 2016/10/04 06:03:17]

Would it make more sense to call this SignalIceRegathering?

[honghaiz3, 2016/10/05 05:01:53]

Done.

+
   virtual uint32_t generation() { return generation_; }
   virtual void set_generation(uint32_t generation) { generation_ = generation; }
   sigslot::signal1<PortAllocatorSession*> SignalDestroyed;
@@ -370,6 +386,12 @@ class PortAllocator : public sigslot::has_slots<> {
   const std::string& origin() const { return origin_; }
   void set_origin(const std::string& origin) { origin_ = origin; }
 
+  virtual void ReportIceRegatheringReason(IceRegatheringReason reason) {}
+
+  void set_metrics_observer(webrtc::MetricsObserverInterface* observer) {
+    metrics_observer_ = observer;
+  }
+
  protected:
   virtual PortAllocatorSession* CreateSessionInternal(
       const std::string& content_name,
@@ -377,6 +399,10 @@ class PortAllocator : public sigslot::has_slots<> {
       const std::string& ice_ufrag,
       const std::string& ice_pwd) = 0;
 
+  webrtc::MetricsObserverInterface* metrics_observer() {
+    return metrics_observer_;
+  }
+
   uint32_t flags_;
   std::string agent_;
   rtc::ProxyInfo proxy_;
@@ -397,6 +423,8 @@ class PortAllocator : public sigslot::has_slots<> {
   int allocated_pooled_session_count_ = 0;
   std::deque<std::unique_ptr<PortAllocatorSession>> pooled_sessions_;
   bool prune_turn_ports_ = false;
+
+  webrtc::MetricsObserverInterface* metrics_observer_ = nullptr;
 };
 
 }  // namespace cricket