Fix multiple Initialize() calls and reenable VEA usage in MediaRecorder for Win8

content/renderer/media_recorder/video_track_recorder.cc

Index: content/renderer/media_recorder/video_track_recorder.cc
diff --git a/content/renderer/media_recorder/video_track_recorder.cc b/content/renderer/media_recorder/video_track_recorder.cc
index 3b1b0a5578ee8617ee68c64058455517a096172e..f9e20f5c75e4638ef62e624eb4e1f676c672908b 100644
--- a/content/renderer/media_recorder/video_track_recorder.cc
+++ b/content/renderer/media_recorder/video_track_recorder.cc
@@ -18,6 +18,7 @@
 #include "base/trace_event/trace_event.h"
 #include "cc/paint/paint_canvas.h"
 #include "cc/paint/paint_surface.h"
+#include "content/child/child_process.h"
 #include "content/renderer/media/renderer_gpu_video_accelerator_factories.h"
 #include "content/renderer/render_thread_impl.h"
 #include "media/base/bind_to_current_loop.h"
@@ -30,10 +31,6 @@
 #include "third_party/libyuv/include/libyuv.h"
 #include "ui/gfx/geometry/size.h"
 
-#if defined(OS_WIN)
-#include "base/win/windows_version.h"
-#endif
-
 #if BUILDFLAG(RTC_USE_H264)
 #include "third_party/openh264/src/codec/api/svc/codec_api.h"
 #include "third_party/openh264/src/codec/api/svc/codec_app_def.h"
@@ -121,12 +118,6 @@ CodecEnumerator::CodecEnumerator() {
   return;
 #endif
 
-#if defined(OS_WIN)
-  // See https://crbug.com/698441.
-  if (base::win::GetVersion() < base::win::VERSION_WIN10)
-    return;
-#endif
-
   content::RenderThreadImpl* const render_thread_impl =
       content::RenderThreadImpl::current();
   if (!render_thread_impl) {
@@ -1303,6 +1294,16 @@ void VideoTrackRecorder::InitializeEncoder(
   DVLOG(3) << __func__ << frame->visible_rect().size().ToString();
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
 
+  if (encoder_) {
+    auto* const child_process = ChildProcess::current();
+    if (child_process) {
+      child_process->io_task_runner()->PostTask(
+          FROM_HERE, base::Bind(&VideoTrackRecorder::Encoder::StartFrameEncode,
+                                encoder_, frame, capture_time));
+    }
+    return;
+  }

[mcasas, 2017/03/23 21:14:08]

I'd do:

  // Avoid reinitializing |encoder_|, https://crbug.com/698441.
  DCHECK(RenderThread::Get());
  if (encoder_ && RenderThread::Get()->GetIOTaskRunner()) {
    RenderThread::Get()->GetIOTaskRunner()->PostTask(
        FROM_HERE, base::Bind(&VideoTrackRecorder::Encoder::StartFrameEncode,
                              encoder_, frame, capture_time));
    return;
  }

If DCHECK() doesn't verify in unit tests, add a 
MockRenderThread [1], wdyt?  RenderThread 
conveys clearlier what you want to do than 
ChildProcess IMHO.

[1]
https://cs.chromium.org/chromium/src/content/public/test/mock_render_thread.h...

[emircan, 2017/03/24 18:14:11]

Done. RenderThreadImpl directly calls ChildProcess::io_task_runner() so I wanted
to skip the middle step, see
https://cs.chromium.org/chromium/src/content/renderer/render_thread_impl.cc?r....


Also, we should still return if |!RenderThread::Get()->GetIOTaskRunner()| so I
nested the loop.

+
   MediaStreamVideoSink::DisconnectFromTrack();
 
   const gfx::Size& input_size = frame->visible_rect().size();