media/gpu VDA unittest: Do not call ReusePictureBuffer on a dimissed picture buffer

A VDA client should not ReusePictureBuffer() on a dismissed picture buffer.
VDA doesn't have to handle this case.

BUG=chromium:834170
TEST=VDA unittest on eve and kevin
TEST=VDA unittest on non-Chrome OS platforms in CQ.

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: Ia3bc2534684b5448c01fdc86d7efc7db4389c21c
Reviewed-on: https://chromium-review.googlesource.com/1063890Reviewed-by: Pawel Osciak <posciak@chromium.org>
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566655}

media/gpu/video_decode_accelerator_unittest.cc

@@ -611,6 +611,12 @@ void GLRenderingVDAClient::ReturnPicture(int32_t picture_buffer_id) {
     return;
   LOG_ASSERT(1U == pending_textures_.erase(picture_buffer_id));
 
+  if (active_textures_.find(picture_buffer_id) == active_textures_.end()) {
+    // The picture associated with picture_buffer_id is dismissed.
+    // Do not execute ReusePictureBuffer().
+    return;
+  }
+
   if (pending_textures_.empty() && state_ == CS_RESETTING) {
     SetState(CS_RESET);
     DeleteDecoder();