Removed RTCStatsCollector::ProducePartialResultsOnWorkerThread.

No stats are collected by it, remove to reduce unnecessary thread hops.

BUG=webrtc:6875, chromium:627816

Review-Url: https://codereview.webrtc.org/2583193002
Cr-Commit-Position: refs/heads/master@{#15862}
diff --git a/webrtc/api/rtcstatscollector.cc b/webrtc/api/rtcstatscollector.cc
index cf97057..85113e6 100644
--- a/webrtc/api/rtcstatscollector.cc
+++ b/webrtc/api/rtcstatscollector.cc
@@ -425,17 +425,8 @@
     // necessarily monotonically increasing.
     int64_t timestamp_us = rtc::TimeUTCMicros();
 
-    num_pending_partial_reports_ = 3;
+    num_pending_partial_reports_ = 2;
     partial_report_timestamp_us_ = cache_now_us;
-    invoker_.AsyncInvoke<void>(RTC_FROM_HERE, signaling_thread_,
-        rtc::Bind(&RTCStatsCollector::ProducePartialResultsOnSignalingThread,
-            rtc::scoped_refptr<RTCStatsCollector>(this), timestamp_us));
-
-    // TODO(hbos): No stats are gathered by
-    // |ProducePartialResultsOnWorkerThread|, remove it.
-    invoker_.AsyncInvoke<void>(RTC_FROM_HERE, worker_thread_,
-        rtc::Bind(&RTCStatsCollector::ProducePartialResultsOnWorkerThread,
-            rtc::scoped_refptr<RTCStatsCollector>(this), timestamp_us));
 
     // Prepare |channel_names_| and |media_info_| for use in
     // |ProducePartialResultsOnNetworkThread|.
@@ -456,9 +447,11 @@
                           pc_->session()->data_channel()->transport_name()));
     }
     media_info_.reset(PrepareMediaInfo_s().release());
+
     invoker_.AsyncInvoke<void>(RTC_FROM_HERE, network_thread_,
         rtc::Bind(&RTCStatsCollector::ProducePartialResultsOnNetworkThread,
             rtc::scoped_refptr<RTCStatsCollector>(this), timestamp_us));
+    ProducePartialResultsOnSignalingThread(timestamp_us);
   }
 }
 
@@ -491,18 +484,6 @@
   AddPartialResults(report);
 }
 
-void RTCStatsCollector::ProducePartialResultsOnWorkerThread(
-    int64_t timestamp_us) {
-  RTC_DCHECK(worker_thread_->IsCurrent());
-  rtc::scoped_refptr<RTCStatsReport> report = RTCStatsReport::Create(
-      timestamp_us);
-
-  // TODO(hbos): There are no stats to be gathered on this thread, remove this
-  // method.
-
-  AddPartialResults(report);
-}
-
 void RTCStatsCollector::ProducePartialResultsOnNetworkThread(
     int64_t timestamp_us) {
   RTC_DCHECK(network_thread_->IsCurrent());
diff --git a/webrtc/api/rtcstatscollector.h b/webrtc/api/rtcstatscollector.h
index 4268a21..0a99ae9 100644
--- a/webrtc/api/rtcstatscollector.h
+++ b/webrtc/api/rtcstatscollector.h
@@ -82,7 +82,6 @@
   // Stats gathering on a particular thread. Calls |AddPartialResults| before
   // returning. Virtual for the sake of testing.
   virtual void ProducePartialResultsOnSignalingThread(int64_t timestamp_us);
-  virtual void ProducePartialResultsOnWorkerThread(int64_t timestamp_us);
   virtual void ProducePartialResultsOnNetworkThread(int64_t timestamp_us);
 
   // Can be called on any thread.
diff --git a/webrtc/api/rtcstatscollector_unittest.cc b/webrtc/api/rtcstatscollector_unittest.cc
index 8916136..749b3d5 100644
--- a/webrtc/api/rtcstatscollector_unittest.cc
+++ b/webrtc/api/rtcstatscollector_unittest.cc
@@ -396,15 +396,12 @@
     if (!delivered_report_)
       return false;
     EXPECT_EQ(produced_on_signaling_thread_, 1);
-    EXPECT_EQ(produced_on_worker_thread_, 1);
     EXPECT_EQ(produced_on_network_thread_, 1);
 
     EXPECT_TRUE(delivered_report_->Get("SignalingThreadStats"));
-    EXPECT_TRUE(delivered_report_->Get("WorkerThreadStats"));
     EXPECT_TRUE(delivered_report_->Get("NetworkThreadStats"));
 
     produced_on_signaling_thread_ = 0;
-    produced_on_worker_thread_ = 0;
     produced_on_network_thread_ = 0;
     delivered_report_ = nullptr;
     return true;
@@ -434,20 +431,6 @@
         new RTCTestStats("SignalingThreadStats", timestamp_us)));
     AddPartialResults(signaling_report);
   }
-  void ProducePartialResultsOnWorkerThread(int64_t timestamp_us) override {
-    EXPECT_TRUE(worker_thread_->IsCurrent());
-    {
-      rtc::CritScope cs(&lock_);
-      EXPECT_FALSE(delivered_report_);
-      ++produced_on_worker_thread_;
-    }
-
-    rtc::scoped_refptr<RTCStatsReport> worker_report =
-        RTCStatsReport::Create(0);
-    worker_report->AddStats(std::unique_ptr<const RTCStats>(
-        new RTCTestStats("WorkerThreadStats", timestamp_us)));
-    AddPartialResults(worker_report);
-  }
   void ProducePartialResultsOnNetworkThread(int64_t timestamp_us) override {
     EXPECT_TRUE(network_thread_->IsCurrent());
     {
@@ -471,7 +454,6 @@
   rtc::CriticalSection lock_;
   rtc::scoped_refptr<const RTCStatsReport> delivered_report_;
   int produced_on_signaling_thread_ = 0;
-  int produced_on_worker_thread_ = 0;
   int produced_on_network_thread_ = 0;
 };