Configure threads with their own warning deadlines.

Design document:
https://docs.google.com/document/d/1c_Jk-eqoBl3mZcEW73OO_WOnWVO9nTU854DHcyqjQBo/edit?resourcekey=0-j2bRwX0nxCldQ_VjoPFAOQ#

Bug: webrtc:12405
Change-Id: Idab950a3293d7ca9328dfeb19ec6d3084f7e0e5f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/203522
Reviewed-by: Tommi <tommi@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33218}

pc/connection_context.cc

diff --git a/pc/connection_context.cc b/pc/connection_context.cc
index 5f9dcb9..858f25d 100644
--- a/pc/connection_context.cc
+++ b/pc/connection_context.cc
@@ -125,6 +125,14 @@
       worker_thread(), network_thread());
 
   channel_manager_->SetVideoRtxEnabled(true);
+  // Set warning levels on the threads, to give warnings when response
+  // may be slower than is expected of the thread.
+  // Since some of the threads may be the same, start with the least
+  // restrictive limits and end with the least permissive ones.
+  // This will give warnings for all cases.
+  signaling_thread_->SetDispatchWarningMs(100);
+  worker_thread_->SetDispatchWarningMs(30);
+  network_thread_->SetDispatchWarningMs(10);
 }
 
 ConnectionContext::~ConnectionContext() {