Vaapi: fix TRACE_COUNTER1 naming

This CL fixes a TRACE_COUNTER1 naming, it should be "Vaapi input buffers"
(see [1]) but is "Input buffers", which makes it appear as different in
traces, as opposed to the intended accumulative effect.

[1] https://cs.chromium.org/search/?sq=package:chromium&type=cs&q=%22Vaapi+input+buffers%22

Change-Id: If490041547701d5e10ca04b500dcbca4cb0942c8
Reviewed-on: https://chromium-review.googlesource.com/c/1354265
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612061}

media/gpu/vaapi/vaapi_video_decode_accelerator.cc

@@ -374,7 +374,7 @@ bool VaapiVideoDecodeAccelerator::GetCurrInputBuffer_Locked() {
   DCHECK(!input_buffers_.empty());
   curr_input_buffer_ = std::move(input_buffers_.front());
   input_buffers_.pop();
-  TRACE_COUNTER1("media,gpu", "Input buffers", input_buffers_.size());
+  TRACE_COUNTER1("media,gpu", "Vaapi input buffers", input_buffers_.size());
 
   if (curr_input_buffer_->IsFlushRequest()) {
     DVLOGF(4) << "New flush buffer";