Enhance WebMediaPlayer::buffered() to account for evicted ranges.

media/blink/buffered_resource_loader.cc

Index: media/blink/buffered_resource_loader.cc
diff --git a/media/blink/buffered_resource_loader.cc b/media/blink/buffered_resource_loader.cc
index d88266d06b22dbe60cd90967b7de340973b58806..b624613fba1e3a5077674faec6d79eb4c33e7b06 100644
--- a/media/blink/buffered_resource_loader.cc
+++ b/media/blink/buffered_resource_loader.cc
@@ -468,7 +468,8 @@ void BufferedResourceLoader::didReceiveData(
   }
 
   // Notify latest progress and buffered offset.
-  progress_cb_.Run(offset_ + buffer_.forward_bytes() - 1);
+  progress_cb_.Run(std::max(0L, offset_ - buffer_.backward_bytes()),
+                   offset_ + buffer_.forward_bytes() - 1);
   Log();
 }