media: Increase preloading and max buffer for high-bitrate videos

media/blink/multibuffer_reader.h

Index: media/blink/multibuffer_reader.h
diff --git a/media/blink/multibuffer_reader.h b/media/blink/multibuffer_reader.h
index cd64982086dcb4d721a5cae35964cc20f3141823..8135d562dd127f348aba93ee5abe56f334b8b372 100644
--- a/media/blink/multibuffer_reader.h
+++ b/media/blink/multibuffer_reader.h
@@ -96,6 +96,8 @@ class MEDIA_BLINK_EXPORT MultiBufferReader
   int64_t preload_low() const { return preload_low_; }
 
  private:
+  friend class MultibufferDataSourceTest;
+
   // Returns the block for a particular byte position.
   MultiBufferBlockId block(int64_t byte_pos) const {
     return byte_pos >> multibuffer_->block_size_shift();