Removed invalid thread DCHECKs in rtc_peer_connection_handler.cc

content/renderer/media/rtc_peer_connection_handler.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/rtc_peer_connection_handler.h"
 
 #include <string.h>
 
 #include <string>
 #include <utility>
@@ skipping 348 matching lines @@
       const scoped_refptr<base::SingleThreadTaskRunner>& main_thread,
       const blink::WebRTCSessionDescriptionRequest& request,
       const base::WeakPtr<RTCPeerConnectionHandler>& handler,
       const base::WeakPtr<PeerConnectionTracker>& tracker,
       PeerConnectionTracker::Action action)
       : main_thread_(main_thread),
         webkit_request_(request),
         tracker_(handler, tracker, action) {
   }
 
   void OnSuccess(webrtc::SessionDescriptionInterface* desc) override {

[perkj_chrome, 2016/08/15 05:37:57]

webrtc::SessionDescriptionInterface* desc should have been const
scoped_refptr<webrtc::SessionDescriptionInterface>& desc instead to make this
more clear.
But I think this was actually correct from the beginning. 
Base::Bind will treat * desc  as a ref counted object unless you use
base::Unretained.

[hbos_chromium, 2016/08/15 14:16:55]

Oh, back to the drawing board.

[hbos_chromium, 2016/08/16 13:43:51]

The template magic of base::Bind is beyond me, but I did some printf debugging.

At main_thread_->PostTask, if I pass |this| both AddRef and Release occurs
before we return. The Release is unexpected. If I pass
|scoped_refptr<CreateSessionDescriptionRequest>(this)| AddRef occurs but no
Release, as it should be.

[hbos_chromium, 2016/08/17 09:51:15]

Nevermind. The different printfs can be explained by races between threads or
whatnot.

     if (!main_thread_->BelongsToCurrentThread()) {
       main_thread_->PostTask(FROM_HERE,
-          base::Bind(&CreateSessionDescriptionRequest::OnSuccess, this, desc));
+          base::Bind(&CreateSessionDescriptionRequest::OnSuccess,
+                     scoped_refptr<CreateSessionDescriptionRequest>(this),
+                     desc));
       return;
     }
 
     tracker_.TrackOnSuccess(desc);
     webkit_request_.requestSucceeded(CreateWebKitSessionDescription(desc));
     webkit_request_.reset();
     delete desc;
   }
   void OnFailure(const std::string& error) override {
     if (!main_thread_->BelongsToCurrentThread()) {
       main_thread_->PostTask(FROM_HERE,
-          base::Bind(&CreateSessionDescriptionRequest::OnFailure, this, error));
+          base::Bind(&CreateSessionDescriptionRequest::OnFailure,
+                     scoped_refptr<CreateSessionDescriptionRequest>(this),
+                     error));
       return;
     }
 
     tracker_.TrackOnFailure(error);
     webkit_request_.requestFailed(base::UTF8ToUTF16(error));
     webkit_request_.reset();
   }
 
  protected:
   ~CreateSessionDescriptionRequest() override {
@@ skipping 19 matching lines @@
       const base::WeakPtr<PeerConnectionTracker>& tracker,
       PeerConnectionTracker::Action action)
       : main_thread_(main_thread),
         webkit_request_(request),
         tracker_(handler, tracker, action) {
   }
 
   void OnSuccess() override {
     if (!main_thread_->BelongsToCurrentThread()) {
       main_thread_->PostTask(FROM_HERE,
-          base::Bind(&SetSessionDescriptionRequest::OnSuccess, this));
+          base::Bind(&SetSessionDescriptionRequest::OnSuccess,
+                     scoped_refptr<SetSessionDescriptionRequest>(this)));
       return;
     }
     tracker_.TrackOnSuccess(NULL);
     webkit_request_.requestSucceeded();
     webkit_request_.reset();
   }
   void OnFailure(const std::string& error) override {
     if (!main_thread_->BelongsToCurrentThread()) {
       main_thread_->PostTask(FROM_HERE,
-          base::Bind(&SetSessionDescriptionRequest::OnFailure, this, error));
+          base::Bind(&SetSessionDescriptionRequest::OnFailure,
+                     scoped_refptr<SetSessionDescriptionRequest>(this),
+                     error));
       return;
     }
     tracker_.TrackOnFailure(error);
     webkit_request_.requestFailed(base::UTF8ToUTF16(error));
     webkit_request_.reset();
   }
 
  protected:
   ~SetSessionDescriptionRequest() override {
     DCHECK(main_thread_->BelongsToCurrentThread());
@@ skipping 1449 matching lines @@
 }
 
 void RTCPeerConnectionHandler::ResetUMAStats() {
   DCHECK(thread_checker_.CalledOnValidThread());
   num_local_candidates_ipv6_ = 0;
   num_local_candidates_ipv4_ = 0;
   ice_connection_checking_start_ = base::TimeTicks();
   memset(ice_state_seen_, 0, sizeof(ice_state_seen_));
 }
 }  // namespace content