Removed invalid thread DCHECKs in rtc_peer_connection_handler.cc

content/renderer/media/rtc_peer_connection_handler.cc

Index: content/renderer/media/rtc_peer_connection_handler.cc
diff --git a/content/renderer/media/rtc_peer_connection_handler.cc b/content/renderer/media/rtc_peer_connection_handler.cc
index 37b9d05cf8ecaee67b048bbefe03ff8a552d94b4..bf872633b2ab5dc1800c0ad9aa5abf1d296710d3 100644
--- a/content/renderer/media/rtc_peer_connection_handler.cc
+++ b/content/renderer/media/rtc_peer_connection_handler.cc
@@ -392,7 +392,11 @@ class CreateSessionDescriptionRequest
 
  protected:
   ~CreateSessionDescriptionRequest() override {
-    DCHECK(main_thread_->BelongsToCurrentThread());
+    // This object is reference counted and its callback methods |OnSuccess| and
+    // |OnFailure| may be invoked on any thread, for non-main threads the

[perkj_chrome, 2016/08/17 11:16:14]

I had problem reading the sentence  
"This object is reference counted and its callback methods |OnSuccess| and
 |OnFailure| may be invoked on any thread, for non-main threads the ...."

May I suggest something like  // |OnFailure| will be invoked on libjingles
signaling thread and posted to the main thread. Since the main thread may
complete before the signaling thread has deferenced this object there is no
guarante.... 

[hbos_chromium, 2016/08/17 13:53:26]

Done.

+    // callback is posted to the main thread. Since the post may complete before
+    // the non-main thread has dereferenced this object there is no guarantee
+    // that this object is destructed on the main thread.
     DLOG_IF(ERROR, !webkit_request_.isNull())
         << "CreateSessionDescriptionRequest not completed. Shutting down?";
   }
@@ -441,7 +445,11 @@ class SetSessionDescriptionRequest
 
  protected:
   ~SetSessionDescriptionRequest() override {
-    DCHECK(main_thread_->BelongsToCurrentThread());
+    // This object is reference counted and its callback methods |OnSuccess| and
+    // |OnFailure| may be invoked on any thread, for non-main threads the
+    // callback is posted to the main thread. Since the post may complete before
+    // the non-main thread has dereferenced this object there is no guarantee
+    // that this object is destructed on the main thread.
     DLOG_IF(ERROR, !webkit_request_.isNull())
         << "SetSessionDescriptionRequest not completed. Shutting down?";
   }