Implement browser-side logging to WebRtc log

content/browser/renderer_host/media/media_stream_manager.cc

Index: content/browser/renderer_host/media/media_stream_manager.cc
diff --git a/content/browser/renderer_host/media/media_stream_manager.cc b/content/browser/renderer_host/media/media_stream_manager.cc
index 8a865fc2903a495faf5e9eb90a614de71607d4db..6cea0ad994a28dfbc0381bfc5ab1fc39098218cb 100644
--- a/content/browser/renderer_host/media/media_stream_manager.cc
+++ b/content/browser/renderer_host/media/media_stream_manager.cc
@@ -14,17 +14,20 @@
 #include "base/rand_util.h"
 #include "base/run_loop.h"
 #include "base/threading/thread.h"
+#include "content/browser/browser_main_loop.h"
 #include "content/browser/renderer_host/media/audio_input_device_manager.h"
 #include "content/browser/renderer_host/media/device_request_message_filter.h"
 #include "content/browser/renderer_host/media/media_stream_requester.h"
 #include "content/browser/renderer_host/media/media_stream_ui_proxy.h"
 #include "content/browser/renderer_host/media/video_capture_manager.h"
 #include "content/browser/renderer_host/media/web_contents_capture_util.h"
+#include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/media_device_id.h"
 #include "content/public/browser/media_observer.h"
 #include "content/public/browser/media_request_state.h"
+#include "content/public/browser/render_process_host.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/media_stream_request.h"
 #include "media/audio/audio_manager_base.h"
@@ -36,6 +39,13 @@
 #include "base/win/scoped_com_initializer.h"
 #endif
 
+static void DoAddLogMessage(const std::string& message) {
+  // Must be on the UI thread to access BrowserMainLoop.
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  content::BrowserMainLoop::GetInstance()->media_stream_manager()->
+      AddLogMessageOnUIThread(message);
+}
+
 namespace content {
 
 namespace {
@@ -1392,8 +1402,19 @@ void MediaStreamManager::Closed(MediaStreamType stream_type,
 void MediaStreamManager::DevicesEnumerated(
     MediaStreamType stream_type, const StreamDeviceInfoArray& devices) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DVLOG(1) << "DevicesEnumerated("
-           << ", {stream_type = " << stream_type <<  "})";
+  std::stringstream devices_msg;
+  devices_msg << "DevicesEnumerated("
+              << "{stream_type = " << stream_type << "})" << std::endl;
+  for (StreamDeviceInfoArray::const_iterator it = devices.begin();
+       it != devices.end(); ++it) {
+    devices_msg << "  " << it->device.name << " ("
+                << it->device.id << ")" << std::endl;
+  }
+  if (devices.empty())
+    devices_msg << "No devices found.";
+
+  DVLOG(1) << devices_msg;
+  AddLogMessage(devices_msg.str());
 
   // Only cache the device list when the device list has been changed.
   bool need_update_clients = false;
@@ -1466,6 +1487,34 @@ void MediaStreamManager::DevicesEnumerated(
   DCHECK_GE(active_enumeration_ref_count_[stream_type], 0);
 }
 
+// static
+void MediaStreamManager::AddLogMessage(const std::string& message) {
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(::DoAddLogMessage, message));
+}
+
+void MediaStreamManager::AddLogMessageOnUIThread(const std::string& message) {
+  // Must be on the UI thread to access RenderProcessHost from process ID.
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  // Add logs for each pending request.
+  for (DeviceRequests::iterator it = requests_.begin(); it != requests_.end();
+       ++it) {
+    DeviceRequest* request = it->second;
+    // Log the message to all renderers that are requesting a MediaStream or
+    // device enumeration.
+    if (request->request_type == MEDIA_GENERATE_STREAM ||
+        request->request_type == MEDIA_ENUMERATE_DEVICES) {
+      content::RenderProcessHostImpl* render_process_host_impl =
+          static_cast<content::RenderProcessHostImpl*>(
+              content::RenderProcessHost::FromID(
+                  request->requesting_process_id));
+      render_process_host_impl->WebRtcLogMessage(message);
+    }
+  }
+}
+
 void MediaStreamManager::HandleAccessRequestResponse(
     const std::string& label,
     const MediaStreamDevices& devices) {