fix canplaythrough

media/blink/buffered_data_source_host_impl.h

Index: media/blink/buffered_data_source_host_impl.h
diff --git a/media/blink/buffered_data_source_host_impl.h b/media/blink/buffered_data_source_host_impl.h
index 7dc39ea331a6ab447e0998e6ca19ce10e254acdf..f3bf3f42bcb470cb90eb6964b8294b9a0708c87e 100644
--- a/media/blink/buffered_data_source_host_impl.h
+++ b/media/blink/buffered_data_source_host_impl.h
@@ -6,7 +6,9 @@
 #define MEDIA_BLINK_BUFFERED_DATA_SOURCE_HOST_IMPL_H_
 
 #include <stdint.h>
+#include <deque>
 
+#include "base/callback.h"
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "media/base/ranges.h"
@@ -35,7 +37,7 @@ class MEDIA_BLINK_EXPORT BufferedDataSourceHost {
 class MEDIA_BLINK_EXPORT BufferedDataSourceHostImpl
     : public BufferedDataSourceHost {
  public:
-  BufferedDataSourceHostImpl();
+  explicit BufferedDataSourceHostImpl(const base::Closure& progress_cb);
   ~BufferedDataSourceHostImpl() override;
 
   // BufferedDataSourceHost implementation.
@@ -50,7 +52,20 @@ class MEDIA_BLINK_EXPORT BufferedDataSourceHostImpl
 
   bool DidLoadingProgress();
 
+  // Returns true if we have enough buffered bytes to play from now
+  // until the end of media
+  bool CanPlayThrough(base::TimeDelta current_position,
+                      base::TimeDelta media_duration,
+                      double playback_rate) const;
+
  private:
+  // Returns number of bytes not yet loaded in the given interval.
+  int64_t UnloadedBytesInInterval(const Interval<int64_t>& interval) const;
+
+  // Returns an estimate of the download rate.
+  // Returns 0.0 if an estimate cannot be made.
+  double DownloadRate() const;
+
   // Total size of the data source.
   int64_t total_bytes_;
 
@@ -61,6 +76,8 @@ class MEDIA_BLINK_EXPORT BufferedDataSourceHostImpl
   // True when AddBufferedByteRange() has been called more recently than
   // DidLoadingProgress().
   bool did_loading_progress_;
+  std::deque<std::pair<base::TimeTicks, uint64_t>> download_history_;
+  base::Closure progress_cb_;
 
   DISALLOW_COPY_AND_ASSIGN(BufferedDataSourceHostImpl);
 };