Implement browser-side logging to WebRtc log

content/browser/renderer_host/render_process_host_impl.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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 1502 matching lines @@
 void RenderProcessHostImpl::DisableAecDump() {
   // Posting on the FILE thread and then replying back on the UI thread is only
   // for avoiding races between enable and disable. Nothing is done on the FILE
   // thread.
   BrowserThread::PostTaskAndReply(
       BrowserThread::FILE, FROM_HERE,
       base::Bind(&DisableAecDumpOnFileThread),
       base::Bind(&RenderProcessHostImpl::SendDisableAecDumpToRenderer,
                  weak_factory_.GetWeakPtr()));
 }
+
+void RenderProcessHostImpl::SetWebRtcLogMessageCallback(
+    base::Callback<void(const std::string&)> callback) {
+  DCHECK(webrtc_log_message_callback_.is_null());
+  webrtc_log_message_callback_ = callback;
+}
+
+void RenderProcessHostImpl::WebRtcLogMessage(const std::string& message) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (!webrtc_log_message_callback_.is_null()) {
+    BrowserThread::PostTask(BrowserThread::IO,
+                            FROM_HERE,
+                            base::Bind(webrtc_log_message_callback_, message));

[jam, 2014/01/17 05:47:44]

how do we guarantee that the callback is valid on the IO thread? RPH is used on
the UI thread, so it's best if we can make the lifetime of the callback valid
just as long which means calling it on the UI thread

[vrk (LEFT CHROMIUM), 2014/01/22 02:25:42]

OK, yeah that makes sense. Moved the thread hop to WebRtcLogMessageHost.

+  };
+}
 #endif
 
 IPC::ChannelProxy* RenderProcessHostImpl::GetChannel() {
   return channel_.get();
 }
 
 void RenderProcessHostImpl::AddFilter(BrowserMessageFilter* filter) {
   channel_->AddFilter(filter->GetFilter());
 }
 
@@ skipping 493 matching lines @@
     return;
   Send(new MediaStreamMsg_EnableAecDump(file_for_transit));
 }
 
 void RenderProcessHostImpl::SendDisableAecDumpToRenderer() {
   Send(new MediaStreamMsg_DisableAecDump());
 }
 #endif
 
 }  // namespace content