Implement browser-side logging to WebRtc log

content/browser/renderer_host/media/audio_input_device_manager.cc

Index: content/browser/renderer_host/media/audio_input_device_manager.cc
diff --git a/content/browser/renderer_host/media/audio_input_device_manager.cc b/content/browser/renderer_host/media/audio_input_device_manager.cc
index cfe00caea329693934194a3c67c18d8758e0dddd..b5ad555017db558ab5739ac2238d76795447985c 100644
--- a/content/browser/renderer_host/media/audio_input_device_manager.cc
+++ b/content/browser/renderer_host/media/audio_input_device_manager.cc
@@ -6,6 +6,7 @@
 
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
+#include "content/browser/renderer_host/media/media_stream_manager.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/common/media_stream_request.h"
 #include "media/audio/audio_device_name.h"
@@ -138,12 +139,15 @@ void AudioInputDeviceManager::EnumerateOnDeviceThread(
       break;
   }
 
+  MediaStreamManager::AddLogMessage(

[perkj_chrome, 2014/01/20 11:07:08]

Why do we have to log here? 
Why not do it in MediaStreamManager::DevicesEnumerated? 

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

Sure, I can do that. I originally put more logging here but then moved it out of
this CL. Agree it makes more sense on MSM::DevicesEnumerated.

That said, I wanted to put an example of MediaStreamManager::AddLogMessage in
this CL. Device enumeration is not the only thing we want to log, but I was
going to put other log messages in separate CLs because they span all OSes
(didn't want to make the CL too big). So I added to this CL log messages on
video device error. PTAL.

+      "AIDM::EODTT found the following devices:");

[Henrik Grunell, 2014/01/17 08:51:25]

Same comments as in VideoCaptureManager for this and the next change.

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

Done.

   scoped_ptr<StreamDeviceInfoArray> devices(new StreamDeviceInfoArray());
   for (media::AudioDeviceNames::iterator it = device_names.begin();
        it != device_names.end(); ++it) {
     // Add device information to device vector.
     devices->push_back(StreamDeviceInfo(
         stream_type, it->device_name, it->unique_id));
+    MediaStreamManager::AddLogMessage(it->device_name + "(" + it->unique_id);
   }
 
   // If the |use_fake_device_| flag is on, inject the fake device if there is