Introduce GpuVideoDecodeAcceleratorFactory.

media/video/video_decode_accelerator.cc

Index: media/video/video_decode_accelerator.cc
diff --git a/media/video/video_decode_accelerator.cc b/media/video/video_decode_accelerator.cc
index 0d3887d02133e6a3381a3e5afa0f15504124c07c..c7a531c7ffdf46eb825602bf859d7ef75431881c 100644
--- a/media/video/video_decode_accelerator.cc
+++ b/media/video/video_decode_accelerator.cc
@@ -34,9 +34,11 @@ void VideoDecodeAccelerator::SetCdm(int cdm_id) {
   NOTREACHED() << "By default CDM is not supported.";
 }
 
-bool VideoDecodeAccelerator::CanDecodeOnIOThread() {
-  // GPU process subclasses must override this.
-  LOG(FATAL) << "This should only get called in the GPU process";
+bool VideoDecodeAccelerator::TryInitializeDecodeOnSeparateThread(
+    const base::WeakPtr<Client>& decode_client,
+    const scoped_refptr<base::SingleThreadTaskRunner>& decode_task_runner) {
+  // Implementations in the process that VDA runs in must override this.
+  LOG(FATAL) << "This may only be called in the same process as VDA impl.";
   return false;  // not reached
 }