Add gpu::MailboxHolder to hold state for a gpu::Mailbox

media/base/video_frame.h

Index: media/base/video_frame.h
diff --git a/media/base/video_frame.h b/media/base/video_frame.h
index b51bfe96d2dc5e94dd066c5c47eb0f3acc0b4b67..e6504bb27a08f96f4617e1af2878e0681861f4bc 100644
--- a/media/base/video_frame.h
+++ b/media/base/video_frame.h
@@ -55,34 +55,6 @@ class MEDIA_EXPORT VideoFrame : public base::RefCountedThreadSafe<VideoFrame> {
   // Returns the name of a Format as a string.
   static std::string FormatToString(Format format);
 
-  // This class calls the TextureNoLongerNeededCallback when this class is
-  // destroyed.  Users can query the current sync point associated with this
-  // mailbox with sync_point(), and should call Resync() with a new sync point
-  // to ensure the mailbox remains valid for the issued commands.
-  // valid for the issued commands.
-  class MEDIA_EXPORT MailboxHolder {
-   public:
-    typedef base::Callback<void(uint32 sync_point)>
-        TextureNoLongerNeededCallback;
-
-    MailboxHolder(const gpu::Mailbox& mailbox,
-                  unsigned sync_point,
-                  const TextureNoLongerNeededCallback& release_callback);
-    ~MailboxHolder();
-
-    const gpu::Mailbox& mailbox() const { return mailbox_; }
-    unsigned sync_point() const { return sync_point_; }
-
-    void Resync(unsigned sync_point) { sync_point_ = sync_point; }
-
-   private:
-
-    gpu::Mailbox mailbox_;
-    unsigned sync_point_;
-    TextureNoLongerNeededCallback release_callback_;
-  };
-
-
   // Creates a new frame in system memory with given parameters. Buffers for
   // the frame are allocated but not initialized.
   // |coded_size| is the width and height of the frame data in pixels.
@@ -108,8 +80,14 @@ class MEDIA_EXPORT VideoFrame : public base::RefCountedThreadSafe<VideoFrame> {
   // |const SkBitmap&| parameter.
   typedef base::Callback<void(const SkBitmap&)> ReadPixelsCB;
 
-  // Wraps a native texture of the given parameters with a VideoFrame.  When the
-  // frame is destroyed |no_longer_needed_cb.Run()| will be called.
+  // CB to be called on the mailbox backing this frame when the frame is
+  // destroyed.
+  typedef base::Callback<void(scoped_ptr<gpu::MailboxHolder>)> ReleaseMailboxCB;
+
+  // Wraps a native texture of the given parameters with a VideoFrame.  The
+  // backing of the VideoFrame is held in the mailbox held by |mailbox_holder|,
+  // and |mailbox_holder_release_cb| will be called with |mailbox_holder| as the
+  // argument when the VideoFrame is to be destroyed.
   // |coded_size| is the width and height of the frame data in pixels.
   // |visible_rect| is the visible portion of |coded_size|, after cropping (if
   // any) is applied.
@@ -119,14 +97,13 @@ class MEDIA_EXPORT VideoFrame : public base::RefCountedThreadSafe<VideoFrame> {
   // |read_pixels_cb| may be used to do (slow!) readbacks from the
   // texture to main memory.
   static scoped_refptr<VideoFrame> WrapNativeTexture(
-      scoped_ptr<MailboxHolder> mailbox_holder,
-      uint32 texture_target,
+      scoped_ptr<gpu::MailboxHolder> mailbox_holder,
+      const ReleaseMailboxCB& mailbox_holder_release_cb,
       const gfx::Size& coded_size,
       const gfx::Rect& visible_rect,
       const gfx::Size& natural_size,
       base::TimeDelta timestamp,
-      const ReadPixelsCB& read_pixels_cb,
-      const base::Closure& no_longer_needed_cb);
+      const ReadPixelsCB& read_pixels_cb);
 
   // Read pixels from the native texture backing |*this| and write
   // them to |pixels| as BGRA.  |pixels| must point to a buffer at
@@ -224,13 +201,10 @@ class MEDIA_EXPORT VideoFrame : public base::RefCountedThreadSafe<VideoFrame> {
   // VideoFrame object and must not be freed by the caller.
   uint8* data(size_t plane) const;
 
-  // Returns the mailbox of the native texture wrapped by this frame. Only
-  // valid to call if this is a NATIVE_TEXTURE frame. Before using the
+  // Returns the mailbox holder of the native texture wrapped by this frame.
+  // Only valid to call if this is a NATIVE_TEXTURE frame. Before using the
   // mailbox, the caller must wait for the included sync point.
-  MailboxHolder* texture_mailbox() const;
-
-  // Returns the texture target. Only valid for NATIVE_TEXTURE frames.
-  uint32 texture_target() const;
+  gpu::MailboxHolder* mailbox_holder() const;
 
   // Returns the shared-memory handle, if present
   base::SharedMemoryHandle shared_memory_handle() const;
@@ -287,8 +261,8 @@ class MEDIA_EXPORT VideoFrame : public base::RefCountedThreadSafe<VideoFrame> {
   uint8* data_[kMaxPlanes];
 
   // Native texture mailbox, if this is a NATIVE_TEXTURE frame.
-  scoped_ptr<MailboxHolder> texture_mailbox_holder_;
-  uint32 texture_target_;
+  scoped_ptr<gpu::MailboxHolder> mailbox_holder_;

[danakj, 2014/01/06 20:13:42]

There's really no reason to use a scoped_ptr here at all anymore, you could just
store a MailboxHolder directly, and pass it in by const-ref in the
WrapNativeTexture method, instead of dealing with scoped_ptrs. This would also
lead to not passing scoped ptrs in the callback anymore.

[sheu, 2014/01/06 22:44:44]

I made this a pointer so things that don't have a mailbox can have this member
be NULL.  The scoped_ptr bits just fall out of that decision -- it's
scoped_ptr-ing the MailboxHolder, not the Mailbox itself.

[danakj, 2014/01/06 23:28:33]

Ok, sure. Using a scoped_ptr here to avoid the size of the MailboxHolder is
fine.

+  ReleaseMailboxCB mailbox_holder_release_cb_;
   ReadPixelsCB read_pixels_cb_;
 
   // Shared memory handle, if this frame was allocated from shared memory.