Support low latency mode decoding in the H/W video decoder on Windows.

content/common/gpu/media/dxva_video_decode_accelerator.cc

Index: content/common/gpu/media/dxva_video_decode_accelerator.cc
diff --git a/content/common/gpu/media/dxva_video_decode_accelerator.cc b/content/common/gpu/media/dxva_video_decode_accelerator.cc
index 69ea9f7d72938268c4e9f9c182e9a29d0a157739..fb51f598811cc2a92f60922a9f49bc126b0660f0 100644
--- a/content/common/gpu/media/dxva_video_decode_accelerator.cc
+++ b/content/common/gpu/media/dxva_video_decode_accelerator.cc
@@ -884,6 +884,12 @@ bool DXVAVideoDecodeAccelerator::CheckDecoderDxvaSupport() {
     RETURN_ON_HR_FAILURE(hr, "Failed to enable DXVA H/W decoding", false);
   }
 
+  hr = attributes->SetUINT32(CODECAPI_AVLowLatencyMode, TRUE);
+  if (SUCCEEDED(hr)) {
+    DVLOG(1) << "Successfully set Low latency mode on decoder.";
+  } else {
+    DVLOG(1) << "Failed to set Low latency mode on decoder. Error: " << hr;
+  }
   return true;
 }