[WebCodecs] Fix null callback crash on Android.

An invalid RequestOverlayInfoCB was provided which triggered a nullptr
crash when the callback was later executed.

R=liberato

Bug: 1135073
Change-Id: I62e4da8b5aec7ae32b8fb82ee6eea38346cd833b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2469446
Auto-Submit: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Frank Liberato <liberato@chromium.org>
Reviewed-by: Frank Liberato <liberato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#817042}

third_party/blink/renderer/modules/webcodecs/video_decoder_broker.cc

@@ -190,18 +190,26 @@ class MediaVideoTaskWrapper {
         std::move(external_decoder_factory));
   }
 
-  std::vector<std::unique_ptr<media::VideoDecoder>> OnCreateDecoders() {
+  void OnRequestOverlayInfo(bool decoder_requires_restart_for_overlay,
+                            media::ProvideOverlayInfoCB overlay_info_cb) {
     DVLOG(2) << __func__;
     DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
-    // TODO(chcunningham): Add plumbing to enable overlays on Android. See
-    // handling in WebMediaPlayerImpl.
-    media::RequestOverlayInfoCB request_overlay_info_cb;
+    // Android overlays are not supported.
+    if (overlay_info_cb)
+      std::move(overlay_info_cb).Run(media::OverlayInfo());
+  }
+
+  std::vector<std::unique_ptr<media::VideoDecoder>> OnCreateDecoders() {
+    DVLOG(2) << __func__;
+    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
     std::vector<std::unique_ptr<media::VideoDecoder>> video_decoders;
     decoder_factory_->CreateVideoDecoders(
         media_task_runner_, gpu_factories_, &null_media_log_,
-        request_overlay_info_cb, target_color_space_, &video_decoders);
+        WTF::BindRepeating(&MediaVideoTaskWrapper::OnRequestOverlayInfo,
+                           weak_factory_.GetWeakPtr()),
+        target_color_space_, &video_decoders);
 
     return video_decoders;
   }