Revert of Remove threading from RendererGpuVideoAcceleratorFactories

content/renderer/media/rtc_video_decoder_factory.cc

Index: content/renderer/media/rtc_video_decoder_factory.cc
diff --git a/content/renderer/media/rtc_video_decoder_factory.cc b/content/renderer/media/rtc_video_decoder_factory.cc
index f59a38fa9b3def68bb53db16618a34165f595c5f..9e12803c8278c5bb281e9594d6511bf4d6af1bff 100644
--- a/content/renderer/media/rtc_video_decoder_factory.cc
+++ b/content/renderer/media/rtc_video_decoder_factory.cc
@@ -6,13 +6,13 @@
 
 #include "base/location.h"
 #include "base/memory/scoped_ptr.h"
+#include "content/renderer/media/renderer_gpu_video_accelerator_factories.h"
 #include "content/renderer/media/rtc_video_decoder.h"
-#include "media/filters/gpu_video_accelerator_factories.h"
 
 namespace content {
 
 RTCVideoDecoderFactory::RTCVideoDecoderFactory(
-    const scoped_refptr<media::GpuVideoAcceleratorFactories>& gpu_factories)
+    const scoped_refptr<RendererGpuVideoAcceleratorFactories>& gpu_factories)
     : gpu_factories_(gpu_factories) {
   DVLOG(2) << "RTCVideoDecoderFactory";
 }
@@ -24,8 +24,12 @@
 webrtc::VideoDecoder* RTCVideoDecoderFactory::CreateVideoDecoder(
     webrtc::VideoCodecType type) {
   DVLOG(2) << "CreateVideoDecoder";
+  // GpuVideoAcceleratorFactories is not thread safe. It cannot be shared
+  // by different decoders. This method runs on Chrome_libJingle_WorkerThread
+  // and the child thread is blocked while this runs. We cannot create new gpu
+  // factories here. Clone one instead.
   scoped_ptr<RTCVideoDecoder> decoder =
-      RTCVideoDecoder::Create(type, gpu_factories_);
+      RTCVideoDecoder::Create(type, gpu_factories_->Clone());
   return decoder.release();
 }