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

media/blink/buffered_resource_loader.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/blink/buffered_resource_loader.h"
 
 #include "base/bits.h"
 #include "base/callback_helpers.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 450 matching lines @@
 
   // Consume excess bytes from our in-memory buffer if necessary.
   if (buffer_.forward_bytes() > buffer_.forward_capacity()) {
     int excess = buffer_.forward_bytes() - buffer_.forward_capacity();
     bool success = buffer_.Seek(excess);
     DCHECK(success);
     offset_ += first_offset_ + excess;
   }
 
   // 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();
 }
 
 void BufferedResourceLoader::didDownloadData(
     blink::WebURLLoader* loader,
     int dataLength,
     int encoded_data_length) {
   NOTIMPLEMENTED();
 }
 
@@ skipping 299 matching lines @@
 
 void BufferedResourceLoader::Log() {
   media_log_->AddEvent(
       media_log_->CreateBufferedExtentsChangedEvent(
           offset_ - buffer_.backward_bytes(),
           offset_,
           offset_ + buffer_.forward_bytes()));
 }
 
 }  // namespace media