Introduce a client minimum picture pool size

content/common/gpu/media/vt_video_decode_accelerator.h

Index: content/common/gpu/media/vt_video_decode_accelerator.h
diff --git a/content/common/gpu/media/vt_video_decode_accelerator.h b/content/common/gpu/media/vt_video_decode_accelerator.h
index 61d0309e96067fa4b04a5fee37a7862d4c4d5325..0519d2e4f6cd2b587bffc018872d620038523d07 100644
--- a/content/common/gpu/media/vt_video_decode_accelerator.h
+++ b/content/common/gpu/media/vt_video_decode_accelerator.h
@@ -38,7 +38,9 @@ class VTVideoDecodeAccelerator : public media::VideoDecodeAccelerator {
   ~VTVideoDecodeAccelerator() override;
 
   // VideoDecodeAccelerator implementation.
-  bool Initialize(media::VideoCodecProfile profile, Client* client) override;
+  bool Initialize(media::VideoCodecProfile profile,
+                  uint32 min_picture_count,
+                  Client* client) override;
   void Decode(const media::BitstreamBuffer& bitstream) override;
   void AssignPictureBuffers(
       const std::vector<media::PictureBuffer>& pictures) override;
@@ -168,6 +170,9 @@ class VTVideoDecodeAccelerator : public media::VideoDecodeAccelerator {
   media::VideoDecodeAccelerator::Client* client_;
   State state_;
 
+  // The number of picture buffers to allocate.
+  uint32_t num_picture_buffers_;
+
   // Queue of pending flush tasks. This is used to drop frames when a reset
   // is pending.
   std::queue<TaskType> pending_flush_tasks_;